Eee-Viii-Energy Auditing & Demand Side Management [10ee842]-Solution

Energy Auditing and Demand Side Management

10EE842

SOLUTION TO QUESTION BANK UNIT-1 1.Write short notes with respect of electrical equipment’s

July, Dec 2015

If you manufacture electrical equipment, you must comply with the Electrical Equipment (Safety) Regulations 1994. These implement into UK law the European Council Directive 2006/95/EEC - commonly referred to as the Low Voltage Directive (LVD). The aim of these regulations is to ensure that electrical equipment designed for use within certain voltage limits is safe to use. This guide covers all the main points of the regulations - including which electrical equipment is affected, definition of electrical equipment, safety requirements and how to comply. The Electrical Equipment (Safety) Regulations 1994 apply to your business if you manufacture electrical equipment designed or adapted for use between 50 and 1,000 volts (in the case of alternating current) or 75 and 1,500 volts (in the case of direct current). The regulations cover domestic electrical equipment and equipment that is intended for use in the workplace, except electrical equipment described in Schedule 2 of these regulations. Coponents The regulations apply to electrical equipment. In general, components are not covered by the regulations. Only components which are in themselves electrical equipment need to satisfy the requirements of the regulations and, in particular, bear European Conformity (CE) marking. The term electrical equipment is not defined in the regulations and should therefore be given the ordinary dictionary meaning. Electrical is defined as ―operated by means of electricity‖ or ―of pertaining to electricity‖. Equipment is defined as ―apparatus‖ which is in turn defined as ―the things collectively necessary for the performance of some activity or function‖. An item is only subject to the requirements of the regulations if it is electrical equipment so defined.

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Electrical components Certain components of electrical equipment may in themselves be considered to be electrical equipment. In such cases, steps should be taken to ensure that they satisfy the requirements of the regulations - if they are to be supplied as separate items. This includes supply for retail sales and to other manufacturers for incorporation into other electrical equipment. 2.Explain the broad features of Indian electricity rule 1956.

July, Dec 2014

The Government of India has enacted the Energy Conservation Act in 2001 to provide legal framework and institutional arrangements for enhancing energy efficiency. This Act led to the creation of Bureau of Energy Efficiency (BEE) as the nodal agency at the center and State Designated Agencies (SDAs) at the State level to implement the provisions of the Act. Under the Act, Central Government, State Government and Bureau of Energy Efficiency have major roles to play in implementation of the Act. The Mission of BEE is to develop policy and strategies based on self-regulation and market principles with the goal of reducing energy intensity of the Indian economy. This will be achieved with active participation of all stakeholders, resulting in rapid and sustained adoption of energy efficiency in all sectors. Electricity Act, 2003 The government has enacted Electricity Act, 2003 which seeks to transform and develop the electricity sector by distancing Government from the task of regulation. Before enactment of this act, electricity supply in India was governed by Indian Electricity Act, 1910, the Electricity (Supply) Act, 1948 and the Electricity Regulatory Commissions Act, 1998. There was a need to consolidate the provisions of above act and consequently, Electricity Act, 2003 was introduced. 3.What is energy conservation? Explain

July 2014

Energy Conservation and Energy Efficiency are separate, but related concepts. Energy conservation is achieved when growth of energy consumption is reduced in physical terms. Energy Conservation, therefore, is the result of several processes or developments, such as productivity increase or technological progress. On the other hand Energy efficiency is achieved when energy intensity in a specific product, process or area of production or consumption is reduced without affecting output, consumption or comfort levels. Promotion of energy efficiency Department of EEE, SJBIT

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will contribute to energy conservation and is therefore an integral part of energy conservation promotional policies. Energy efficiency is often viewed as a resource option like coal, oil or natural gas. It provides additional economic value by preserving the resource base and reducing pollution. For example, replacing traditional light bulbs with Compact Fluorescent Lamps (CFLs) means you will use only 114th of the energy to light a room. Pollution levels also reduce by the same amount (refer Figure 1.11)

Nature sets some basic limits on how efficiently energy can be used, but in most cases our products and manufacturing processes are still a long way from operating at this theoretical limit. Very simply, energy efficiency means using less energy to perform the same function. Although, energy efficiency has been in practice ever since the first oil crisis in 1973, it has today assumed even more importance because of being the most cost-effective and reliable means of mitigating the global climatic change. Recognition of that potential has led to high expectations for the reduction of future CO2 emissions through more energy efficiency improvements than that achieved in the past. The industrial sector accounts for about 41 per cent of global primary energy demand and approximately the same share of CO2 emissions.

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UNIT-2 1.Explain payback analysis. Mention its advantages and Disadvantages

Dec 2015

Payback Period: The simplest technique which can be used to appraise a proposal is payback analysis. The payback period can be defined as the time (number of years) required to recover the initial investment (capital cost), considering only the Annual Net Saving (Yearly benefitsYearly costs). Once the payback period has ended, all the project capital costs will have been recovered and any additional cost savings achieved can be seen as clear 'profit'. The shorter the payback period, the more attractive the project becomes. The length of the maximum permissible payback period generally varies with the company concerned.

Time Value of Money A project usually entails an investment for the initial cost of installation, called the capital cost, and a series of annual costs and/or cost savings (i.e. operating, energy, maintenance, etc.) throughout the life of the project. To assess project feasibility, all these present and future cash flows must be equated to a common basis. The problem with equating cash flows which occur at different times is that the value of money changes with time. The method by which these various cash flows are related is called discounting, or the present value concept. For example, if money can be deposited in the bank at 10% interest, then a Rs. 100 deposit will be worth Rs.110 in one year's time. Thus the Rs.110 in one year is a future value equivalent to the Rs. 100 present value.

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In the same manner, Rs.100 received one year from now is only worth Rs.90.91 in today's money (i.e. Rs.90.91 plus 10% interest equals Rs.100). Thus Rs.90.91 represents the present value of Rs.100 cash flow occurring one year in the future. If the interest rate were something different than 10%, then the equivalent present value would also change. 2.A plant cost Rs 7.56*10 5 and its estimated that after 25 years it will have to be replaced by a new one, at that instant its salvage value will be Rs 1.56* 105 calculate i) annual deposit to be made in order to replace the plant after 25 years ii) the value of the plant after 10 years in the following basis a) Straight line depreciation method. b) Reducing balance method c) Sinking fluid deprecation method at 8% annual compound interest

July 2015

i) Examine few electric bills in immediate past and calculate total number of days,total kWh consumed and average daily kWh [e.g. in an installation with 3 numbers working and 2 numbers standby if bill period is 61 days, total consumption 5,49,000 kWh, then average daily consumption shall be 9000 kWh]. ii) Examine log books of pumping operation for the subject period, calculate totalpump hours of individual pump sets, total pump hours over the period andaverage daily pump hours [Thus in the above example, pump hours of individualpumpsets are : 1(839), 2(800), 3(700), 4(350) and 5(300) then as total hours are2989 pump-hours, daily pump hours shall be 2989 ÷ 61 = 49 pump hours. Averagedaily operations are: 2 numbers opumps working for 11 hours and 3 numbersof pumps working for 9 hours]. iii) From (i) and (ii) above, calculate mean system kW drawn per pumpset [In the example, mean system power drawn per pumpset = 9000 / 49 i.e. 183.67 kW]. iv) From (i), (ii) and (iii) above, calculate cumulative system kW for minimum and maximum number of pumps simultaneously operated. [In the example, cumulative system kW drawn for 2 numbers of pumps and 3 numbers of pumps operating shall be 183.67 x 2 = 367.34 kW and 183.67 x 3 = 551.01 kW respectively]. v) Depending on efficiency of transformer at load factors corresponding to differentcumulative kW, calculate output of transformer for loads of different Department of EEE, SJBIT

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combinationsof pumps. [In the example, if transformer efficiencies are 0.97 and 0.975 for load factor corresponding to 367.34 kW and 551.01 kW respectively, then outputs of transformer for the loads shall be 367.34 x 0.97 i.e. 356.32 kW and 551.01 x 0.975i.e. 537.23 kW respectively. vi) The outputs of transformer, for all practical purpose can be considered as cumulative inputs to motors for the combinations of different number of pumps working simultaneously. Cable losses, being negligible, can be ignored. vii) Cumulative input to motors divided by number of pumpsets operating in the combination shall give average input to motor (In the example, average input tomotor shall be 356.32 ÷ 2 i.e. 178.16 kW each for 2 pumps working and 537.23÷ 3 i.e. 179.09 kW each for 3 pumps working simultaneously. viii) Depending on efficiency of motor at the load factor, calculate average input to pump.[In the example, if motor efficiency is 0.86, average input to pump shal be178.16 x 0.86 i.e. 153.22 kW and 179.07 x 0.86 i.e. 154.0 kW]. If actual discharge is within 4% - 6% of rated discharge, the results are deemed as satisfactory. If discharge varies beyond limit, it indicates that wearing rings are probably worn out. The clearance need to be physically checked by dismantling the pump and measuring diametral clearances in wearing rings and replacing the wearing ring. 3.Explain cash flow model

July 2015,July 2014

Cash flow forecasting or cash flow management is a key aspect of financial management of a business, planning its future cash requirements to avoid a crisis of liquidity. Cash flow forecasting is important because if a business runs out of cash and is not able to obtain new finance, it will become insolvent. Cash flow is the life-blood of all businesses—particularly start-ups and small enterprises. As a result, it is essential that management forecast (predict) what is going to happen to cash flow to make sure the business has enough to survive. How often management should forecast cash flow is dependent on the financial security of the business. If the business is struggling, or is keeping a watchful eye on its finances, the business owner should be forecasting and revising his or her cash flow on a daily basis. However, if the finances of the business are more stable and 'safe', then forecasting and revising cash flow weekly or monthly is enough. Here are the key reasons why a cash flow forecast is so important: Department of EEE, SJBIT

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Identify potential shortfalls in cash balances in advance—think of the cash flow forecast as an "early warning system". This is, by far, the most important reason for a cash flow forecast.

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Make sure that the business can afford to pay suppliers and employees. Suppliers who don't get paid will soon stop supplying the business; it is even worse if employees are not paid on time.

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Spot problems with customer payments—preparing the forecast encourages the business to look at how quickly customers are paying their debts. Note—this is not really a problem for businesses (like retailers) that take most of their sales in cash/credit cards at the point of sale.

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As an important discipline of financial planning—the cash flow forecast is an important management process, similar to preparing business budgets.

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External stakeholders such as banks may require a regular forecast. Certainly, if the business has a bank loan, the bank will want to look at the cash flow forecast at regular intervals.

Definition In the context of corporate finance, cash flow forecasting is the modeling of a company or entity's future financial liquidity over a specific timeframe. Cash usually refers to the company's total bank balances, but often what is forecast is treasury position which is cash plus shortterm investments minus short-term debt. Cash flow is the change in cash or treasury position from one period to the next period. Methods The direct method of cash flow forecasting schedules the company's cash receipts and disbursements (R&D). Receipts are primarily the collection of accounts receivable from recent sales, but also include sales of other assets, proceeds of financing, etc. Disbursements include payroll, payment of accounts payable from recent purchases, dividendsand interest on debt. This direct R&D method is best suited to the short-term forecasting horizon of 30 days or so because this is the period for which actual, as opposed to projected, data is available. The three indirect methods are based on the company's projected income statements and balance sheets.

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The adjusted net income (ANI) method starts with operating income (EBIT or EBITDA) and adds or subtracts changes in balance sheet accounts such as receivables, payables and inventories to project cash flow.

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The pro-forma balance sheet (PBS) method looks straight at the projected book cash account; if all the other balance sheet accounts have been correctly forecast, cash will be correct, too.

Both the ANI and PBS methods are best suited to the medium-term (up to one year) and longterm (multiple years) forecasting horizons. Both are limited to the monthly or quarterly intervals of the financial plan, and need to be adjusted for the difference between accrual-accounting book cash and the often-significantly-different bank balances. 

The third indirect approach is the accrual reversal method (ARM), which is similar to the ANI method. But instead of using projected balance sheet accounts, large accruals are reversed and cash effects are calculated based upon statistical distributions and algorithms. This allows the forecasting period to be weekly or even daily. It also eliminates the cumulative errors inherent in the direct, R&D method when it is extended beyond the shortterm horizon. But because the ARM allocates both accrual reversals and cash effects to weeks or days, it is more complicated than the ANI or PBS indirect methods. The ARM is best suited to the medium-term forecasting horizon.

Uses A cash flow projection is an important input into valuation of assets, budgeting and determining appropriate capital structures in LBOs and leveraged recapitalizations.

Definition In the context of entrepreneurs or managers of small and medium enterprises, cash flow forecasting may be somewhat simpler, planning what cash will come into the business or business unit in order to ensure that outgoing can be managed so as to avoid them exceeding cashflow coming in. Entrepreneurs need to learn fast that "Cash is king" and, therefore, they must become good at cashflow forecasting. Department of EEE, SJBIT

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Methods The simplest method is to have a spreadsheet that shows cash coming in from all sources out to at least 90 days, and all cash going out for the same period. This requires that the quantity and timings of receipts of cash from sales are reasonably accurate, which in turn requires judgement honed by experience of the industry concerned, because it is rare for cash receipts to match sales forecasts exactly, and it is also rare for customers all to pay on time. These principles remain constant whether the cash flow forecasting is done on a spreadsheet or on paper or on some other IT system. A danger of using too much corporate finance theoretical methods in cash flow forecasting for managing a business is that there can be non cash items in the cashflow as reported under financial accounting standard. This goes to the heart of the difference between financial accounting and management accounting. UNIT-3

1.

Write short note on energy audit instruments

July 2015, July 2014

The requirement for an energy audit such as identification and quantification of energy necessitates measurements; these measurements require the use of instruments. These instruments must be portable, durable, easy to operate and relatively inexpensive. The parameters generally monitored during energy audit may include the following: Basic Electrical Parameters in AC &DC systems - Voltage (V), Current (I), Power factor, Active power (kW), apparent power (demand) (kVA), Reactive power (kVAr), Energy consumption (kWh), Frequency (Hz), Harmonics, etc. Parameters of importance other than electrical such as temperature & heat flow, radiation, air and gas flow, liquid flow, revolutions per minute (RPM), air velocity, noise and vibration, dust concentration, Total Dissolved Solids (TDS), pH, moisture content, relative humidity, flue gas analysis - CO2, 02, CO, SO,, NO, combustion efficiency etc. Key instruments for energy audit are listed below. The operating instructions for all instruments must be understood and staff should familiarize themselves with the instruments and their operation prior to actual audit use. Department of EEE, SJBIT

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Energy Auditing and Demand Side Management 2. Explain detailed energy audit.

10EE842

Dec 2015, July 2014

Phase I -Pre Audit Phase Activities A structured methodology to carry out an energy audit is necessary for efficient working. An initial study of the site should always be carried out, as the planning of the procedures necessary for an audit is most important. Initial Site Visit and Preparation Required for Detailed Auditing An initial site visit may take one day and gives the Energy Auditor/Engineer an opportunity to meet the personnel concerned, to familiarize him with the site and to assess the procedures necessary to carry out the energy audit. During the initial site visit the Energy Auditor/Engineer should carry out the following actions: • Discuss with the site's senior management the aims of the energy audit. • Discuss economic guidelines associated with the recommendations of the audit. • Analyze the major energy consumption data with the relevant personnel. • Obtain site drawings where available - building layout, steam distribution, compressed air distribution, electricity distribution etc. • Tour the site accompanied by engineering/production The main aims of this visit are: • To finalize Energy Audit team • To identify the main energy consuming areas/plant items to be surveyed during the audit. • To identify any existing instrumentation/ additional metering required. • To decide whether any meters will have to be installed prior to the audit eg. kWh, steam, oil or gas meters. • To identify the instrumentation required for carrying out the audit. • To plan with time frame

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• To collect macro data on plant energy resources, major energy consuming centers • To create awareness through meetings/ programme Phase II- Detailed Energy Audit Activities Depending on the nature and complexity of the site, a comprehensive audit can take from several weeks to several months to complete. Detailed studies to establish, and investigate, energy and material balances for specific plant departments or items of process equipment are carried out. Whenever possible, checks of plant operations are carried out over extended periods of lime, at nights and at weekends as well as during normal daytime working hours, to ensure that nothing is overlooked. The audit report will include a description of energy inputs and product outputs by major department or by major processing function, and will evaluate the efficiency of each step of the manufacturing process. Means of improving these efficiencies will be listed, and at least a preliminary assessment of the cost of the improvements will be made to indicate the expected pay-back on any capital investment needed. The audit report should conclude with specific recommendations for detailed engineering studies and feasibility analyses, which must then be per-formed to justify the implementation of those conservation measures that require investments. The information to be collected during the detailed audit includes: 1. Energy consumption by type of energy, by department, by major items of process equipment, by end-use 2. Material balance data (raw materials, intermediate and final products, recycled materials, use of scrap or waste products, production of by-products for re-use in other industries, etc.) 3. Energy cost and tariff data 4. Process and material flow diagrams 5. Generation and distribution of site services (eg. compressed air, steam). 6. Sources of energy supply (e.g. electricity from the grid or self-generation) Department of EEE, SJBIT

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7. Potential for fuel substitution, process modifications, and the use of co-generation systems (combined heat and power generation). UNIT-4

1. With a vector diagram, explain various components of power triangle

July 2015,July 2014

The Power Triangle

The advantages of PF improvement by capacitor addition a) Reactive component of the network is reduced and so also the total current in the system from the source end. b) I2R power losses are reduced in the system because of reduction in current. c) Voltage level at the load end is increased. d) KVA loading on the source generators as also on the transformers and lines up to the capacitors reduces giving capacity relief. A high power factor can help in utilizing the full capacity of your electrical system. 2. Explain plant energy performance (PEP) and power flow concept.

July 2014

Electric power supply system in a country comprises of generating units that produce electricity; high voltage transmission lines that transport electricity over long distances; distribution lines that deliver the electricity to consumers; substations that connect the pieces to each other; and energy control centers to coordinate the operation of the components. The Figure shows a simple electric supply system with transmission and distribution network and linkages from electricity sources to end-user. Department of EEE, SJBIT

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The power plants typically produce 50 cycle/second Hertz), alternating-current (AC) electricity with voltages between 11kV and 33kV. At the power plant site, the 3-phase voltage is stepped up to a higher voltage for transmission on cables strung on cross-country towers. High voltage (HV) and extra high voltage (EHV) transmission is the next stage from power plant to transport A.C. power over long distances at voltages like; 220 kV & 400 kV. Where transmission is over 1000 km, high voltage direct current transmission is also favored to minimize the losses. Subtransmission network at 132 kV, 110 kV, 66 kV or 33 kV constitutes the next link towards the end user. Distribution at 11 kV / 6.6 kV / 3.3 kV constitutes the last link to the consumer, who is connected directly or through transformers depending upon the drawl level of service. The transmission and distribution network include sub-stations, lines and distribution transformers. High voltage transmission is used so that smaller, more economical wire sizes can be employed to carry the lower current and to reduce losses. Sub-stations, containing step-down transformers, reduce the voltage for distribution to industrial users. The voltage is further reduced for commercial facilities. Electricity must be generated, as and when it is needed since electricity cannot be stored virtually in the system.

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Energy Auditing and Demand Side Management 3. Write short notes on primary and secondary distribution.

10EE842

July 2014

The main function of an electrical power distribution system is to provide power to individual consumer premises. Distribution of electric power to different consumers is done with much low voltage level. Distribution of electric power is done by distribution networks. Distribution networks consist of following main parts 1. Distribution substation, 2. Primary distribution feeder, 3. Distribution Transformer, 4. Distributors, 5. Service mains. The transmitted electric power is stepped down is substations, for primary distribution purpose. Now these stepped down electric power is fed to the distribution transformer through primary distribution feeders. Over head primary distribution feeders are supported by mainly supporting iron pole (preferably rail pole). The conductors are strand aluminum conductors and they are mounted on the arms of the pole by means of pin insulators. Some times in congested places, underground cables may also be used for primary distribution purposes.

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Distribution transformers are mainly 3 phase pole mounted type. The secondary of the transformer is connected to distributors. Different consumers are fed electric power by means of the service main. These service mains are tapped from different points of distributors. The distributors can also be re-categorized by distributors and sub distributors. Distributors are directly connected to the secondary of distribution transformers whereas sub distributors are tapped from distributors. Service main of the consumers may be either connected to distributors or sub distributors depending upon the position and agreement of consumers. In this discussion of electrical power distribution system, we have already mentioned about both feeders and distributors. Both feeder and distributor carry the electrical load, but they have one basic difference. Feeder feeds power from one point to another without being tapped from any intermediate point. As because there is no tapping point in between, the current at sending end is equal to that of receiving end of the conductor. The distributors are tapped at different points for feeding different consumers; and hence the current varies along their entire length.

Radial Electrical Power Distribution System In early days of electrical power distribution system, different feeders were radially come out from the substation and connected to the primary of distribution transformer directly.

Radial Distribution SystemBut radial electrical power distribution system has one major drawback that in case of any feeder failure, the associated consumers would not get any power as Department of EEE, SJBIT

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there was no alternative path to feed the transformer. In case of transformer failure also, the power supply is interrupted. In other words the consumer in the radial electrical distribution system

would

be

in

darkness

until

the

feeder

or

transformer

was

rectified.

Ring Main Electrical Power Distribution System The drawback of radial electrical power distribution system can be overcome by introducing a ring main electrical power distribution system. Here one ring network of distributors is fed by more than one feeder. In this case if one feeder is under fault or maintenance, the ring distributor is still energized by other feeders connected to it. In this way the supply to the consumers is not affected even when any feeder becomes out of service. In addition to that the ring main system is also provided with different section isolates at different suitable points. If any fault occurs on any section, of the ring, this section can easily be isolated by opening the associated section isolators on both sides of the faulty zone. UNIT-5 & 6

1. Derive tariff. List the characteristics of tariff

Jan 2015,July 2014

Tariff is the rate of payment of schedule of rates on the energy bill of the consumer is prepared. There are different methods of charging different types of consumers depending on the type of load (domestic, commercial or industrial), maximum demand, time at which load is required, power factor of the load and the amount of energy consumed. Aims and objectives of tariff The aims and objectives of tariff are: i) The rates charged by the supplying agency must conform with the energy received by the consumers. ii) The recovery from the different types of consumers should be equitably distributed among them, except in some cases where special concession have to be given to special type of consumers such as farmers, small scale industries, cottage industries etc. iii) While framing the tariff, the supplying agencies should take into account all the costs involved from the point of generation to the point of the consumption. In addition to generation, Department of EEE, SJBIT

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transmission and distribution costs, of metering, meter reading, billing, bill collection and annual charges on capital investment should also be considered. 2.What are the limitations of low power factor? Explain in brief

July 2015, July 2014

Power factor is the percentage of electricity that is being used to do useful work It is defined as the ratio of 'active or actual power' used in the maul measured in watts or kilowatts ( or KW to the 'apparent power expressed in volt-amperes or kilo Va-amperes (VA or KVA) Active Power W Power factor = or Apparent Power VA The apparent power also referred to as total power delivered by utility company has. ° Components 1) Productive Power' that powers the equipment and performs the useful work It is measured in Kw (kilowatts) 2) 'Reactive Power' that generates magnetic fields to produce field necessary for the operation of induction devices (AC motors, transformer, inductive furnaces, ovens etc ) It is measured in KV. (Kilovolt-Ampere-Reactance) Reactive power produces no productive work An inductive motor with power applied and no load on rms shaft should draw almost nil productive power, same no output work is being accomplished until a load is applied The current associated with no-load motor readings is almost entirely "Reactive" Power As a load is applied to shaft of the motor, the 'Reactive" Power requirement will change only a small amount The 'Productive Power' is the power that is transferred from electrical energy to some other form of energy (such as heat energy or mechanical energy) The apparent power is always in always in excess of the productive power for inductive loads and is dependent on the type of machine in use The working power (KM a. reactive power (KV.), together make up apparent power which is measured in kilovoltamperes (KVA) Graphically it can be represented as

Understanding Power Factor Department of EEE, SJBIT

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The cosine of the phase angle 0 between the KVA and the 1,KW components represents the power factor of the load. KVAR represents the non-productive reactive power and 0 is lagging phase angle. The Relationship between KVA KW and KVAR is non-linear and is expressed KVA2= KW2 + KVAR2 A power factor of 0.72 would mean that only 72% of your power is being used to do useful work. Perfect power factor is 1.0. (Unity); meaning 100% of the power is being used for useful work. Any industrial process using electric motors (to drive pumps. fans, conveyors. refrigeration plant etc.) introduces inefficiencies into the electricity supply network by drawing additional currents, called "inductive reactive currents". Although these currents produce no useful power they increase the load on the supplier's switchgear & distribution network and on the consumer's switchgear & cabling. The inefficiency is expressed as the ratio of useful power to total power (KW/KVA) known as Power Factor. Typical uncorrected industrial power factor is 0.8. This means that a 1MVA transformer can only supply 800KW or that a consumer can only draw 80 useful Amps from a 100Amp supply. To put it the other way, a 3-phase 100KW load would draw 172A per phase instead of the 139A expected. For inherently low power factor equipment, the utility company has to generate much more current than is theoretically required. This excess current flows through generators, cables, and transformers in the same manner as the useful current. If steps are not taken to improve the power factor of the load, all the equipment from the power station to the installation sub-circuit wiring, has to be larger than necessary. This results in increased capital expenditure and higher transmission and distribution losses throughout the whole network. To discourage these inefficiencies the electricity companies charge for this wasted power. These charges appear on electricity bills as "reactive power charges", "KVA maximum demand" or "KVA availability charges". For instance known information taken from billing about electrical system: KVA = 1000, KW = 800, KVAR = 600, PF = .80

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Disadvantages of low power factor Many engineers are oblivious to the effects of low power factor. They view it only as a direct charge on their electrical bill, and only when stated as such. Low power factor is a direct cost to the utility company and must be paid for. Direct costs of low power factor Power factor may be billed as one of or combination of, the following: 1) A penalty for power factor below and a credit for power factor above a predetermined value, 2) An increasing penalty for decreasing power factor, 3) A charge on monthly KVAR Hours, 4) KVA demand: A straight charge is made for the maximum value of KVA used during the month. Included in this charge is a charge for KVAR since KVAR increase the amount of KVA. Indirect costs of low power factor Loss in efficiency of the equipment: When an installation operates with a low power factor, the amount of useful power available inside the installation at the distribution transformers is considerably reduced due to the amount of reactive energy that the transformers have to carry. The figure below indicates the available actual power of distribution equipment designed to supply 1000KW 3. What is ABT? Write the broad features of ABT design. 

July 2014

It is a performance-based tariff for the supply of electricity by generators owned and controlled by the central government

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It is also a new system of scheduling and despatch, which requires both generators and beneficiaries to commit to day-ahead schedules.

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It is a system of rewards and penalties seeking to enforce day ahead pre-committed schedules, though variations are permitted if notified One and one half hours in advance.

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The order emphasises prompt payment of dues. Non-payment of prescribed charges will be liable for appropriate action under sections 44 and 45 of the ERC Act.

It has three parts: - A fixed charge (FC) payable every month by each beneficiary to the generator for making capacity available for use. The FC is not the same for each beneficiary. It varies with the share of a beneficiary in a generators capacity. The FC, payable by each beneficiary, will also vary with the level of availability achieved by a generator. - In the case of thermal stations like those of NLC, where the fixed charge has not already been defined separately by GOI notification, it will comprise interest on loan, depreciation, O&M expenses, ROE, Income Tax and Interest on working capital. - In the case of hydro stations it will be the residual cost after deducting the variable cost calculated as being 90% of the lowest variable cost of thermal stations in a region. - An energy charge (defined as per the prevailing operational cost norms) per kwh of energy supplied as per a pre-committed schedule of supply drawn upon a daily basis. - A charge for Unscheduled Interchange (UI charge) for the supply and consumption of energy in variation from the pre-committed daily schedule. This charge varies inversely with the system frequency prevailing at the time of supply/consumption. Hence it reflects the marginal value of energy at the time of supply. How is ABT different from normal proceedings to determine generation tariff? 1. The ABT proceeding has not attempted to consider most of the cost drivers like ROE, Operational Costs, depreciation rate, composition of the Rate Base, capital structure etc. Proceedings to redefine these norms are being held separately. Hence the ABT proceedings have been concerned more with tariff design rather than definition of tariff norms or determination of tariff levels. 2. It's incidence is a function not only of the behaviour of a generator but also of the behaviour of a beneficiary. Disciplined beneficiaries and generators stand to gain. Undisciplined beneficiaries and generators stand to lose. Department of EEE, SJBIT

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Broad features of ABT design. 1. It implements the long held view that electricity tariffs should be two-part comprising of a fixed charge and a separate energy charge. 2. It increases the target availability level at which generators will be able to recover their fixed costs and ROE from 62.79% deemed PLF at present to 80% (85% after one year) for all thermal stations, 85% for Hydro in the first year and 77% (82% after one year) for NLC. 3. Misdeclaration of availability entails severe penalties. 4. 4. It rationalises the relationship between availability level and recovery of fixed cost. The draft notification provided for recovery of (annual fixed costs minus ROE) at 30% availability and recovery of ROE on pro-rata basis between 30% and 70% availability. This order provides for payment of capacity charges between 0% and target availability (as indicated in item 2 above) on pro-rata basis. 5. The draft notification had provided for payment of capacity charges for prolonged outages. This order disallows such payments. 6. It delinks the earning of incentive from availability and links it instead to the actual achievement of generation. Hence incentives will be earned by generators only where there is a genuine demand for additional energy generation unlike the prevailing situation, or the proposed draft received from the GOI, under which it is earned purely because the generator is available. 7. Draft notification linked incentives to equity. This order preserves the status quo of one paise per kwh per each 1% increase in PLF above target availability. 8. It increases the minimum performance criterion for the earning of an incentive from 68.5% deemed PLF at present to 80% (85% after one year) for all thermal stations, 85% for Hydro and 77% (82% after one year) for NLC. 9. It introduces severe financial penalties for grid indiscipline along with significant rewards for behaviour, which enforces grid discipline for both generators as well as beneficiaries. Department of EEE, SJBIT

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10. The order permits market pricing for the trading of surplus energy by beneficiaries and generators. 11. The order urges the GOI to allocate the unallocated capacity a month in advance so that beneficiaries know their exact share in capacity in advance and can take steps to trade surplus power. 12. It will be implemented in stages from April 1,2000 starting from the South. The new norm for incentive will however be applicable from this date for all central stations. In the case of NPC, GOI to decide applicability of the order. 4.An Industrial load takes 1,00,000 units in a year , the average power factor being 0.8lagging. the record maximum demand is 500 KVA . The tariff is Rs.120 KVA of maximum demand plus 2.5 paise /KWh calculate the Annual cost of supply and find out the annual saving in cost by installing phase advancing plant costing Rs.50/KVAR, which raises the P.f. from 0.8 to 0.95 lagging. Allow 10 % per year on the cost of phase advancing plant to cover all additional costs.

July2013

Maximum demand in KVA at a pf of 0.8 =240/0.8=300 Annual bill = Demand charges+ energy charges =Rs 50X 300 + Rs 0.1 X 50000 =Rs 15000+ Rs 5000= Rs 20000 =flat rate /unit= Rs20000/50000=Rs 0.40 paise=40 paise When power factor is increased to 0.95 percent ,the maximum demand in KVA = 240/0.95= 253 Annual bill = Rs 50X 253 + Rs 0.1 X 50000 =17650 Department of EEE, SJBIT

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Annual saving =Rs 20000-17650 = Rs 2350 5.The monthly reading’s of a consumers meter are as follows: maximum demand: 50 Kwh,energy consumed =36000 Kwh, reactive energy 23,400 KVAR. If the tariff is Rs 100/KW of maximum demand plus 6 paise/unit plus 0.5 paise/unit for each 1% of power factor below 86% ,calculate the monthly bill of consumer.

July2014

units consumed/year = Max demand X L.F X Hours in a year = 50 X 0.6 X 8760 KWh =262800 Max demand in Kva =50/pf = 50/0.86= 58.13 Annual bill = maximum demand charges + energy charges = 262800+ 18000= Rs 280800 Monthly charges + 280800/12 = RS 23400 UNIT-7 & 8 1.Briefly explain DSM planning and implementation

July 2015, July 2014

The concept of demand-side management (DSM) has been introduced in the USA, more specifically in the electricity industry, in the mid-eighties. It has been originally defined as the planning, implementation and monitoring of a set of programmes and actions carried out by electric utilities to influence energy demand in order to modify electric load curves in a way which is advantageous to the utilities. Changes in load curves must decrease electric systems running costs - both production and delivery costs -, and also allow for deferring or even avoiding some investments in supply-side capacity expansion. Thus, DSM has been driven by strict economic reasons. Energy efficiency was a privileged instrument for DSM implementation, as will be seen. Hence, in societal terms, this was a typical win-win situation, as consumers would also benefit from cheaper energy services, as overall efficiency would increase. Department of EEE, SJBIT

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DSM has been a major breakthrough that led to a great deal of innovation, both at business management and at technological development, and also to huge environmental benefits. Yet, a great number of DSM tools already existed previously to the concept, and had been in use by many utilities, namely those tools related to remote load control, known as load management (LM). But LM aims predominantly at influencing power use - the amount of energy used by unit of time, at specific times. Energy efficiency was actually a newcomer to the business, brought by DSM to the portfolio of utility management options. There are six main objectives defined in the context of DSM, known as: peak clipping, valley filling, load shifting, flexible load curve, strategic conservation and strategic load growth. Apart from strategic load growth (SLG), all other options require that the utility's system is under pressure and requires either capacity expansion or load relief. Cost-benefit analysis will dictate which options to adopt. In many cases utilities have opted for DSM in order to avoid or postpone important financial stresses. In general, DSM implementation options may be classified into several different broad categories: customer education, direct customer contact, trade ally co-operation, advertising and promotion, alternative pricing, direct incentives. Some measures pin-pointed in the text below are examples of some of them. Different techniques of DSM – time of day pricing Cost of supply is not constant for any type of energy delivery, be it electricity, gas or heated water. Variations of demand per unit time within a given period of time cause variable operating conditions that correspond to variable system running cost. The causes for variations are different among energy forms but variations always exist. Tariff systems with multi rate structure are, in general, an adequate response to variable costs of supply, as they correspond to pass on to consumers an approximate image of supply cost variations -- they are usually based on long term previsions of marginal cost of delivery. In the electricity business multi rate tariffs are already traditional, at least to certain customer classes. The same does not apply with the same extension to other utilities, mainly because of technical and management difficulties. The alternative is the so-called flat rate, meaning a constant price, independent of cost of supply variations. Department of EEE, SJBIT

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Multi rate tariffs potentially lead to a reaction of demand that depends on its actual elasticity with price, which is in principle beneficial to both sides -- supplier and consumers. These tend to see positively the possibility of controlling more effectively their bills. Indirectly, demand reaction will induce variations on the level of emissions. Theoretically there is a reciprocal influence between prices and demand level, depending on elasticity, which corresponds in general to an efficient use of supply resources. 2.Explain energy efficient technology in electrical system.

July2014

Energy demand management, also known as demand side management (DSM), is the modification of consumer demand for energy through various methods such as financial incentives and education. Usually, the goal of demand side management is to encourage the consumer to use less energy during peak hours, or to move the time of energy use to off-peak times such as nighttime and weekends.[1] Peak demand management does not necessarily decrease total energy consumption, but could be expected to reduce the need for investments in networks and/or power plants. The concept of demand-side management (DSM) has been introduced in the USA, more specifically in the electricity industry, in the mid-eighties. It has been originally defined as the planning, implementation and monitoring of a set of programmes and actions carried out by electric utilities to influence energy demand in order to modify electric load curves in a way which is advantageous to the utilities. Changes in load curves must decrease electric systems running costs - both production and delivery costs -, and also allow for deferring or even avoiding some investments in supply-side capacity expansion. Thus, DSM has been driven by strict economic reasons. Energy efficiency was a privileged instrument for DSM implementation, as will be seen. Hence, in societal terms, this was a typical win-win situation, as consumers would also benefit from cheaper energy services, as overall efficiency would increase. DSM has been a major breakthrough that led to a great deal of innovation, both at business management and at technological development, and also to huge environmental benefits. Yet, a great number of DSM tools already existed previously to the concept, and had been in use by many utilities, namely those tools related to remote load control, known as load management Department of EEE, SJBIT

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(LM). But LM aims predominantly at influencing power use - the amount of energy used by unit of time, at specific times. Energy efficiency was actually a newcomer to the business, brought by DSM to the portfolio of utility management options. There are six main objectives defined in the context of DSM, known as: peak clipping, valley filling, load shifting, flexible load curve, strategic conservation and strategic load growth. Apart from strategic load growth (SLG), all other options require that the utility's system is under pressure and requires either capacity expansion or load relief. Cost-benefit analysis will dictate which options to adopt. In many cases utilities have opted for DSM in order to avoid or postpone important financial stresses. 3.Explain energy conservation opportunities in illumination and industrial sector Dec 2014 Here are key components of an effective campus energy conservation program to reduce energy use and GHG emissions from campus operations: Strong Program Leadership An energy officer to develop energy conservation measures and projects and catalyze the entire effort.Full support from facilities leadership, the chief business officer, and the president Enhanced Energy Awareness Aggressive Energy Conservation Policies which address: 

Heating and cooling season temperature settings

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Building HVAC and fan operating schedules

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Computer operations and "green computing"

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Ban on all incandescent bulbs and halogen torchiere lamps (the latter is also a safety issue)

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Energy purchasing (including buying green power)

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Energy efficiency purchasing standards for various types of equipment -- hopefully going beyond Energy Star compliance

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Improved space utilization to avoid new construction or heating/cooling of underused space

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Energy efficiency standards for new construction

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Restrictions on the use of portable space heaters

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Energy practices in on-campus residence halls and student apartments

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Residential appliance policies (e.g. load limits per room, ban refrigerators, TVs, microwaves, etc.)

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Curtailment periods when campus use is minimal and energy shutdowns can be implemented

Engaged Facilities Operations An active facilities energy conservation committee which meets regularly and is encouraged and empowered by the physical plant director (and campus leadership) to push the envelope and aggressively pursue all conservation opportunities Comprehensive implementation of no cost/low cost operational measures – e.g. temperature set-points, equipment run-times and building occupancy hours, etc. -- that push the envelope, i.e. risk complaints Adequate facilities staffing levels – especially HVAC controls technicians, heating and power plant operators, mechanics, and electricians -- to operate the campus efficiently and readily implement energy conservation measures and projects in-house Periodic re-commissioning of all existing buildings to optimize energy efficiency Facilities staff performance appraisals that evaluate staff on commitment to energy conservation Empowerment of highly motivated staff who are anxious to implement energy conservation measures Rewarding of staff who identify conservation opportunities and implement conservation measures Reconsideration of the timing of the academic calendar to better align it with periods of least energy cost operation, e.g. in cold regions this might involve shifting academic activity and campus occupancy away from the coldest months and implementing a partial campus shutdown during that period

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Energy Auditing and Demand Side Management 4.Write short notes on i) Peak clipping ii) Load shifting iii) valley falling.

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July2013

Electric load management, which is often called simply load management, refers to the systems in place that match electricity supplies with demand. A steady supply of power is generally quite straightforward to produce with a typical coal, gas or nuclear plant - simply fire up the generator and make sure you have a steady supply of fuel. However, the demand is not steady: there is more demand during dinnertime, for example, and on hot afternoons when the air conditioners are on. A power company must be able to supply power at all times, however, so they are motivated to shift large electrical loads from high-demand peak times to low-demand off-peak times. The means by which they do this are collectively called load management. Load management generally falls into one of three categories: load clipping, load shifting, and valley filling, which are shown in Figure Most of the strategies described here are load clipping or load shifting strategies. Practically speaking, this usually means raising energy prices during peak usage times and on high-volume users. Raising rates during peak hours is possible because peak usage is quite predictable, with modern predictions typically within 1% Electric load management is a complex subject for several reasons: the technology is not trivial, economic complexities strongly influence the overall picture, and much of the data comes from sources (power companies) that are out to make money, not necessarily to elucidate their business strategies. At the same time, one cannot understand the power generation and distribution system without considering fluctuations in demand, and the interplay between supply and demand.

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