Substation Presentation V2

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High Voltage Substation

Modification and Presentation by Asst. Prof. Dr. Dr. Teratam Teratam Bunyagul KMUTNB

Copyright by: AREVA Energietechnik GmbH Dr. Uwe Kaltenbron Kaltenbron Berlin, Germany

Prof.Dr.-Ing. Armin Schnettler RWTH Aachen University

Air Insulated Substation Substation

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AIS

Introduction Substation:

nodal points in power system

Internationally standardized voltage level: 66 kV, 110 kV, 132 kV, 150 kV, 220 kV, 380 kV 500 kV*, 800 kV*

* For

very long transmission distances

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Introduction

Introduction Tasks of substation: 

Distribution power towards load circuit



Separation of different network groups (reduction of short circuit power)



Coupling of different voltage level via power transformers



Measuring, signaling and monitoring of network data (e.g. U, I, P, Q, f)

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Substation design Conventional substations (AIS): 





Construction according to standardized minimal distances (clearance) between phase and earth

Normally used for outdoor substations, just in very few cases used for indoor substations Base on single power system equipments 



Replacement of single equipment by equipments from other manufacturers is possible. GIS : replacement bay-by-bay; even this is diffi cult



Simply to expand (in case that space is not an issue)



Excellent overview, simple handling and easy access

Minimum clearance in air according to IEC 61936-1 Nominal voltage of system

Highest voltage for equipment

Rated short- duration power frequency withstand voltage

Rated lightning impulse withstand voltage

Un r.m.s.

Um r.m.s.

r.m.s.

1.2/50 s (peak value)

kV

kV

kV

kV

mm

110

123

185

450

900

230

550

1100

275

650

1300

325

750

1500

360

850

1700

395

950

1900

460

1050

2100

220

245

Minimum phase-to-earth and phase-to-phase clearance (N)

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Minimum clearance in air according to IEC 61936-1 Nominal voltage of system

Highest voltage for equipment

Rated short duration power frequency withstand voltage

Rated switching impulse withstand voltage

Minimum phase-toearth clearance

Un r.m.s.

Um r.m.s.

1.2/50 s (peak value)

Phase-toearth 250/2500 s (peak value)

kV

kV

kV

kV

380

420

1050/1175

850

1900 2200

2400

1360

2900

3400

1175/1300

950

2200 2400

2900

1425

3100

3600

1300/1425

1050

2600

3400

1575

3600

4200

Conductor To structure

Rod To structure

Rated switching impulse withstand voltage

Phase-tophase 250/2500 s (peak value)

mm

Minimum phase-tophase clearance

Conductor To Conductor parallel

kV

Rod To Conductor

mm

Planning of substations Basis requirements for new substations: 

Optimal location of substations within power system (load flow, shortcircuit, customer requirements, long term planning, land space)



Selection of substation design



Calculation of short-circuit currents and long term development (ratings)



Selection of power system requirements





Adaption of design according to available space, fixing of busbar configuration (e.g. using wire conductor or tubular conductor) Detailed planning of  

Primary and secondary equipment



Auxiliary equipment



Basement, steel structure



Building, earthing system

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Planning of substatation Important standards for power system installations: IEC 61936-1

Power installations exceeding 1 kV a.c. - Part 1: Common rules

Substation configurations Design planning of a substation normally starts with the development of the electrical single line diagram: 

Single line diagram: 



Number of busbars and substation bays including the relevant equipment

Selection of substation layout depends on 



Its importance within the power system (power system reliability in case of failures and maintenance activities) Power system operation

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Substation configuration Single busbar configuration

Substation configuration Double busbars configuration

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Substation configuration Double busbars configuration with U-from

Substation configuration Triple busbars configuration

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Substation configuration Double busbars configuration with bypass bus

Substation configuration Double busbars configuration with bypass disconnector

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Substation configuration 1 1/2 – breaker configuration

Substation configuration Ring busbar configuration

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Substation configuration H - configuration

Substation configuration Busbar coupling/sectionalizing Busbar coupling

Busbar sectionalizing and coupling

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Switchyard layouts Named based on the switchyard configuration and the location of the busbar disconnectors Criteria to choose the switchyard layout are: 

Available land



Requirements by power system operator



Economical requirement

Based on voltage level, main purpose (e.g. main transformer station, load-centre substation) different switchyard layouts have shown technical and economical advantages.

Classical layout 115-kV-outdoor AIS bay

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Classical layout 

 

Centre-break disconnector or vertical-break disconnector are arranged side by side in line with the feeder below the busbars Application up to 220 kV Today, not so often used

Advantages: Narrow spacing between bays Excellent ways for maintenance of busbars and busbar disconnectors  

Disadvantages: Higher costs for portal structures and for means for means of tensioning the wires At least one busbar are spanned by connecting wires 



In-line layout 115-kV-outdoor AIS bay

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In-line layout 



Poles of busbar Centre-break disconnectors stand in line with the busbars Application up to 132 kV

Advantages: Lower costs for steel structures are means of tensioning the wires (in case of tubular portals are needed only for the outgoing overhead lines) Busbars not spanned by connecting wires 



Disadvantages: Wide spacing of bays Maintenance at busbars more difficult  longer planned outage times In case of short circuit higher loading of post insulators   

Transverse layout 115-kV-outdoor AIS bay

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Transverse layout  



Busbar disconnectors are in a row at right angles to the busbar Busbar can be of wire or tube (busbar can be directly installed on busbar disconnectors) Application up to 245 kV

Advantages: Narrow spacing between bays(width) Excellent access to busbars  

Disadvantages: Wide spacing of substation (depth) All busbars are spanned by connecting wires  

Diagonal layout 110-kV-outdoor AIS bay, busbar above

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Pantograph disconnector

Diagonal layout 110-kV-outdoor AIS bay, busbar below

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Diagonal layout 

Single column disconnectors as busbar disconnector are arranged diagonally with reference to the basbars



Busbar arrange below (buabars are mounted on the disconnectors) or above the busbar disconnector



Busbar can be of wire or tube



Reduced land usage



Application especially for 220 kV and 380 kV (land usage)

Diagonal layout Busbar above: 

Busbar portals with relatively big hight; dimensioned for high mechanical forces



More difficult access to busbar



Excellent maintenance access to busbar disconnectors

Busbar below: 





Busbar mounted directly on disconnector → reduced means for portals Excellent access to busbars Maintenance on disconnectors require de-energzing of complete busbar

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Busbars All layouts can be installed with either wire or tube busbars: Wire busbar: Today mainly Al/St- oder Aldrey (AlMgSi)-wires Span width up to 50 m For high current ratings up to four conductors required (per phase) Conductors mounted using tension insulators (porcelain, cap-and–pin insulator) In order to protect insulator against flashovers use of arcing horns common In case of short circuit currents additional mechanical stresses will appear. Double pole short-circuit currents critical due to maximum deflection (approximation) after fault clearance.    





Busbars Tubular busbars (preferred for new substation):   

   



AIMgSi-tube (outer diameter 50-300 mm, thickness 4-12 mm) Advantageous for high current ratings Due to lower mechanical forces (spanning forces) reduced means for steel and fundaments Additional means for post insulators and mounting material Spanning distance exceeding 20 m Use of welded tubes up to lengths of 140 m Higher wind load forces, damping of oscillations using inserted wires In short circuit cases additional bending moments. Resonant frequencies of busbar in the range of power frequency or double power frequenices have to be avoided.

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