TECHNICAL SPECIFICATION FOR POWER CAPACITOR BANKS … · •The capacitor banks shall include the...

Ministry of Electricity and Renewable Energy زارة الكهرباء والطاقة المتجددة و و

Egyptian Electricity Holding Company شركة القابضة لكهرباء مصر ال

EDMS 21- 100 - 1 EEHC DISTRIBUTION MATERIALS SPECIFICATION

Date: 17-11-2015

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EDMS 21-100-1

TECHNICAL SPECIFICATION

FOR

POWER CAPACITOR BANKS AND ACCESSORIES

12 K.V

Issue: NOV-2015 / Rev- 1

يجب تحديدها بواسطة شركة التوزيع قبل الطرح. ( Option items) توجد بنود اختيارية




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Technical Specifications

1- General description

The required automatic p.f controller as defined in item 1.1 is a shunt

capacitor bank (two groups)

Each group have a rating of 1.1, to achieve switching steps and provided

with a contactor.

Switching form step to step should be provided to operate automatically and

manually. The operation sequence which could be carried out after closing

the isolator and C.B is:

• Put the selector on automatic position for both steps.

• Measuring the reactive power of the load by the regulator (controller).

• If the power factor is lagging and reactive power =MVAR of

step1+0.1MVAR,then :

▪ Step1 contactor closes after time delay.

▪ Measuring again the reactive power of the load.

• If the compensation still not enough.

• (Reactive power=MVAR of step2+0.1MVAR),then

▪ Step2 contactor closes after time delay.

▪ Measuring again the reactive power of the load.

• If the P.F. becomes close to unity, both steps 1&2 remain in service.

• If the P.F becomes leading then step should be switched off.

• If the over voltage or over THD greater than 8% the contactors trip.

Note:

Delay time should be carried out by time delay relay and should be greater




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than capacitor discharge time

Three phase capacitors:

The capacitors should be delta connection, and its rate shall be as

distribution company requirements.

Ratings :

• The maximum operating voltage of t h e capacitor unit is 12 kv

service voltage is 11 kv),the KVAR effective value calculated at service

voltage

• Rated frequency is 50 Hz.

• The upper limit of operating temperature e category of the required capacitor

unit shall be 55 °C according to {!EC 60871-1) the lower limit is 00 C

• Capacitor unit shall be suit able for operation voltages as follows (IEC

60871-1) . 100 % UN ......................................... Continuous Operation

110 % UN....................................For 1 2 hours every 24 hrs

115 % UN .............................. For 30 minutes in every 24 hrs

120 % UN ........................................................... ….For 5 min.

130 % UN......................................................................F..o. r 1 min .

• (The latest version of IEC-should be applicable in any case)

• Capacitor unit should be suitable for continuous operation at r.m.s current

of the current that occurs at rated sinusoidal voltage and rated frequency.

The capacitor unit should withstand a maximum current of 1.43In due to

the combined effect of harmonics and over voltages up to and including

110 %UN (IEC 60871-1 ).

• The capacitance tolerance shall be CLAUSE 7. 2 IEC 60871-1 2005.

Losses :W / KVAR:

• Losses in steady state rated voltage and frequency at 25 °C indoor ambient




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temperature should not be more than 0.2W/KVAR (Lower values are

preferable).

External fuses:

• The capacitor unit shall be protected by external fuses. The fuses shall in

event of capacitor failure, function correctly at both, the operating

voltage range (0.9)√ 2 UN of the bank and momentary over voltages up

to the limit of 2√2 UN . The fuses must withstand the relatively high

inrush current

Capacitor bank

• The capacitor bank should be completely assembled in one metallic

cubicle (as drawing). Which contains: the high voltage connection,

contactors, inrush current coils and auxiliaries, the container should

have a protection degree and insulation level of IP 31 for indoor type.

• The capacitor banks shall include the racks for the capacitor units and

metal enclosure for live high voltage parts of the bank. Also meatal.

Insulation Material:

The Insulation of the capacitor unit shall be of synthetic. foils (poly

propylene - film), however the tenderer can submit paper insulation as an

alternative.

All PCB impregnates are not allowed for use in Egypt. Insulation shall be

of the (Ali - film). Type, each capacitor shall be completely vacuum

impregnated with no voids or air pockets to prevent corona and permit

mounting in any position .

Bushings:

Capacitor shall be of the three bushings type. Bushing shall be of well

process porcelain.

All bushings shall be hermetically soldered to the steel case. Heavy tin-

plated clamp type, terminals suitable for standard copper conductors. All

capacitor terminals shall be provided with insulating terminal cover




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lnsulation Level :

The insulation level of the units should be equivalent to that of the bank

otherwise extra-insulation to the units is necessary.

The Insulation level· (Creepage distance) should be not less than 2.5

cm/kv for indoor installation. The withstand voltage should be as follows:

Power frequency a.c withstand test voltage (r.m.s) for 12 KV capacitor bank

is 28 kv (!EC 60871 -1} latest edition.

Withstand impulse test voltage crest value for 12 kv capacitor bank is 75 kv

(!EC 60871-1)

For external insulation. The power frequency withstand voltage under

pollution severity for 50 micro siemens (.is or higher for 12 kv capacitor

banks is 1.25 Un=15 kv.

Internal Discharge Device:

• Each capacitor unit shall be equipped with internal discharge resistor

which shall drain the residual voltage from the operating voltage to 75

Volts within 10 minutes after the capacitor is disconnected from the

source of supply according to IEC publication. The maximum

discharge time is 10 minutes for both capacitors and banks.

• Protection box for low voltage and secondary connections of the bank

must be mounted at the works.

• Terminal blocks, internal wiring and cabling to the bank shall be

included. The tender shall provide the banks at the work with the

necessary high voltage wiring of the capacitor un it s and other

equipment and terminals of the bank.

• The metallic parts of banks such as racks, connect ion and relay boxes

shall be hot-zinced (at least 600g/m2), unless of aluminum.

• The degree of protection of the connection and relay boxes shall be IP

31 for indoor installations.

• The capacitors shall be installed in such a way that there is adequate




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dissipation by radiation and convection of the heat produced by the

capacitor losses. For indoor capacitor banks, on e or more fans can be

mounted in the bottom of the capacitor compartment to provide

ventilation.

• The Construction for every compartment must take into consideration

the facilities of easy replacement of the capacitor units and the

maintenance carried out.

• The capacitor banks shall be equipped with coils to limit the inrush

current, contactors for the steps connection.

Circuit Breaker

A- The 12 K.V. circuit breakers shall be vacuum or SF6 type.

B- The necessary closing, tripping and blocking coils shall be {110 V DC). with an

electric spring charge universal motor drive {110 V DC ) or magnetic actuator

mechanism consist of three coil s (one per pole) and all phases connected to each other

using synchronizing shaft. The circuit breakers shall be mechanically and electrically

trip free and with provision for manual operation.

C- Necessary auxiliary contacts for controlling, signaling& free contacts{4N O-4N C)

at least in low voltage compartment and all accessories needed for operation shall be

provided.

D- Each panel which attached with SF6 C.B shall be equipped with double Flag relay

indication one for low gas pressure and another for insufficient gas pressure (in case of

insufficient gas pressure, C.B's shall be locked) .

E- The rupturing capacity of all the 12 K.V. circuit breakers shall be symmetrical

short circuit current of 25 K.A. for 3 Sec.

F-The normal current ratings is 630A .

G- All main fixed and moving contacts shall be silver plated.

H- The C.B used in the capacitor bank must have a good switching capability up to the




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highest bank rating without restricting and thus without over voltages occurring.

I-The required C.B should be SF6/ vacuum type with operating mechanism of sprin g

operated device (motor-charged spring).

J-The C.B should withstand the following stresses:

*Sharp daily ambient- air temperature fluctuations for indoor/ outdoor banks

• The higher variation of the reactive power e.g the higher number of

operations during the day.

• The high frequency oscillations which may overheat and overstress

the capacitors.

• Standard IEC62271-100.

Unless otherwise specified the attached specification should be

comply with IEC Standard.

(SF6 automatic fused Load break switch as option according to

distribution company requirement)

The 3-phase L.B.S. should be capable of opening and closing the capacitor

bank 2nd carrying current under normal circuit conditions and carrying

for 1 Sec. short circuit current. The required L.B.S. should have auxiliary

contact and Complete with earthing switch and Complete with 12 KV.

H.R.C. fuses and fuse rupture capacity shall be> 40 KA.

The required specifications of the L.B.S. are:

Standard IEC 6 2271-60265

System voltage (KV) : 11

One-minute power frequency withstands voltage (KV) :

To earth and between phases 28 KV




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Arms the isolating distance 32 KV

1 . 2/.50 (.is impulse withstand voltage (peak):

To earth and between phases 75 k.v

Across the isolating distance 85 k.v

Rated normal current (A): 400 A

Rated S.C. current (KA for 1 s) 25KA

-The earthing switch should have mechanical lock which prevents

its switching while the main switch is on.

-The L.B.S. can't be operated unless the capacitor bank contactor is

disconnected. This key lock shall prevent the L.B.S from breaking the

capacitor current and provide safety.




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Circuit

Breaker Step 1 Step 2

Drawing Capacitor Bank Container




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Table (1)

Capacitor Bank

No. ITEM EEHC Specs. Supplier Specs. Remarks

1 Rated capacity MVAR Natural and

forced ventilation

must be taken into

consideration for

the bank

2 Rated Voltage 12KV

3

Max.

Allowable over

current

130% IO

4 Frequency 50HZ

5 Connection of

capacitor Delta

6 Discharge time

to 75 600 sec.

7 Insulation level

of Bank 28/75 kv

8 Mounting

Inside the

container

indoor

9 Capacitor Bank

According to IEC 60871-1




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Table (2) Inrush current coils

No. ITEM EEHC Specs. Supplier

Specs. Remarks

1 Inductance X µH

Calculated by

the

manufacturer

inside the

container

2 Max. Operating

Voltage 12KV

3 Service Voltage 11 KV

4 AC withstand

voltage 28 KV/1 min.

5 Impulse withstand

voltage 75 KV/1.2/50 µs

Table (3)

Control box


Specs.

Remarks

1 Operating

Principle • With controller (Table4)

• Automatic & Manual

Operation

• Stand-by operation

• Key lock interlock with

L.B.S

2 Protection • Over voltage protection

(Table5)

• Over THDV

• Reserve polarity of C.T

3 Auxiliary

Voltage

110-220 V DC




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Table (4)

Q-Controller


Specs.

Remarks

1 Type 6 Steps With

display

2 Power Supply 110-220 V DC(+10% -

20%)

3 Control Voltage Taken from first two

phases (380v)

4 Control Current Taken form third phase

5 Frequency 50 HZ

6 Rated Current 5A

7 Rated Burden 3 VA

8 Manual

Operation

Momentary push buttons

9 Operating

Sequence

1:1times, 20-40 Sec. delay

10 Contact Ring 7.5 A, 250VAC normally

open

11 Ambient

Temperature

-5°C: 55°C

12 Accuracy Class 2.5

13 Protection

Class

IP40




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Table (5)

Over Voltage Protection Relay No. ITEM EEHC Specs. Supplier Specs. Remarks

1

1st Stage

Voltage setting

range

Time range

100-115%U0

0-5 Sec.

2

2nd Stage

Voltage setting

range

Time range

115-130%U0

0-5 Sec.

3 Auxiliary Voltage 110-220 V DC

4 Contact rating 7.5A – 250V DC/AC,

NO

Table (6)

SF6 Contactor for Switching Process of Capacitor Bank

No. ITEM EEHC Specs. Supplier Specs. Remarks

1 Rated MVAR

2 System Voltage 12KV

3 AC withstand voltage 28 KV/1 min.

4 Impulse with stand voltage 125 KV/1.2/50

µSec.

5 Rated normal current 200 A

6 Rated S.C. Current 8 KA for 3 Sec.

7 Auxiliary Voltage 110-220 V DC

8 Poles Insulation medium

pressurized SF6 provided

9 Capacitor Bank According

to

IEC 62271-100

TECHNICAL SPECIFICATION FOR POWER CAPACITOR BANKS … · •The capacitor banks shall include the...

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