What is the Acceptable Range of Power Frequency Variation During the Normal Conditions Set by Standards in Different Voltage Levels Which Standard

What is the acceptable range of power frequency variation during the normal conditions set by standards in different voltage levels? Which standard? 1 month ago 

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ColinUnfollow Follow Colin Colin Flatters • That depends on your location and and the corresponding legislation ......... In the UK  for example ESQCR apply to power powe r quality parameters. The DNOs have to maintain v oltage, frequency, harmonic distortion within acceptable limits, i believe +/- 1% or 0.5 Hz. 1 month ago• ago• Unlike• Like   

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PratikUnfollow Follow Pratik  Pratik Bandyopadhyay • Hi Arash, As correctly indicated by Colin, the variation is different in different regains. In India it is defined in grid code and CEA. The acceptable limit is +3/-5%. However, in general the system grid, i.e 400 kv, is working at +/-0.5%. If it is weak grid and isolated, the frequency may fall depending on the generation-load balance at a particular instance. IEC 60034 defines the  boundary of frequency variation of generator. As per the frequency plot specified in IEC60034, generator will produce its rated power within frequenc y variation of +/- 2%. Beyond the same generator can run, but will have more temperature than specified. 1 month ago• Unlike• Like   

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ArashUnfollow Follow Arash Arash Khoshkbar Sadigh • Thanks Colin and Pratik for your comments. 1 month ago• Unlike• Like   

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OfaUnfollow Follow Ofa

Ofa Khoirun Ni'am • I just want to share in my CFSPP project the setting of both over and under  frequency relay are 45Hz/51Hz, it means will trip at 45 Hz and 51Hz, 1 month ago• Unlike• Like   

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OfaUnfollow Follow Ofa Ofa Khoirun Ni'am • In the other hand, the setting of the Synchronizing Relay is (-2.5/+2.5 Hz) or (-5%/+5%), But actually i still confuse, if the 47.5 Hz first reached, The power Plant will out of Synchronous from the system (it means the GCB or CB nearest of Generator will opened/tripped). if the situation is like that, i think the under frequency relay will never work  (because it has 45 Hz of the setting). or any comment anyone here?? 1 month ago• Unlike• Like   

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ArashUnfollow Follow Arash Arash Khoshkbar Sadigh • Thanks Ofa for your comment. Would you please explain briefly about the CFSPP project? 1 month ago• Unlike• Like   

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OfaUnfollow Follow Ofa Ofa Khoirun Ni'am • The CFSPP is Coal Fire Steam Power Plant, it's My Project in South Kalimantan, Indonesia, 2x65MW 1 month ago• Unlike• Like   

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 NimaUnfollow Follow Nima  Nima Mahmoudpour • Hi Arash I have done a research on the Northern Ireland Grid Protection and can give you an example for  the permissible frequency variation on the Northern Ireland Grid (as defined on their grid standard). The following sentence are exactly wha t that document says. Hope it helps you.  ______________________________________________________________  * SUPPLY STANDARDS CC5.2 Each User shall ensure that its Plant and Apparatus at Connection Points is capable of  operating under any variation in the System Frequency and voltage as set out in CC5.3 to CC5.5. CC5.3 Frequency Variations CC5.3.1 The Frequency of the NI System shall be nominally 50 Hz and shall normally be controlled within the limits of 49.5 Hz to 50.5 Hz and in accordance with the Electricity Supply Regulations (N.I.) 1991. CC5.3.2 In exceptional circumstances, System Frequency could rise to 52 Hz or fall to 47 Hz but sustained operation outside the range specified in the Electricity Supply Regulations (N.I.) 1991 is not envisaged. Users should take these factors into account in the design of Plant and Apparatus. 1 month ago• Unlike• Like  

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BillUnfollow Follow Bill Bill Swingle, P.E. • PG&E (a large USA utility), maintains tight frequency con trol at 60 hertz. If their opperators see frequency drop just a fraction they take corrective action. If their freq. drops to 59.75 they take extreme action such as shedding load! Meaning customers go dark. They almost never need to do that. Usually only during natural dissasters. Fluctuations are kept minimal. They remain at ~59.95 hertz consistantly. Their regulations reflect this of course. Even though equipment can operate over a bit of a range they avoid fluxuations stringently. Frequency is quite critical. It reflects the current, real time, "health" of the distribution system. Much effort goes into protecting it. 1 month ago• Unlike• Like   

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SudiptoUnfollow Follow Sudipto Sudipto Ghosh • Hi Ofa, The synchonising relay (Is it really called synchronising relay)in your case should idealy trip the tie breaker and should not trip the GCB if you want to operate the generator in island mode mode after it gets desynchronised.In your case The GCB will trip at 45 Hz.The operation of generator  with low frequency will be limited by heating of core due to over fluxing of generator  ,transformers and also the minimum speed of the eq uipments your generator is supplying in islanded condition. But I am surprised that the the synchronising relay( We call it interconnection relay or grid islanding relay)over frequency limit is set at 52.5 Hz. It is too high a setting when connected to grid.

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OfaUnfollow Follow Ofa Ofa Khoirun Ni'am • @Sudipto, Thank you for your comments. the value of setting when we test was -2.5 Hz/+2.5Hz, but now applied -0.1Hz/+0.1Hz (i checked in the display), for the synchronized devices. Sorry for the synchronizing relay i think is not properly name . Yes i think so, for the value -/+2.5Hz is so high, it can cause switching at the system, when the power plant succeed to synchronized to the grid. 1 month ago