Section

SWITCHGEAR (for BESS)

 Contents

1. GENERAL .................................................................................................................................... 2
2. SWITCHGEAR - CIRCUIT BREAKER (CB) .................................................................. 2
3. SWITCHGEAR-INSTRUMENT TRANSFORMERS ...................................................... 2
4. SWITCHGEAR – ISOLATOR .......................................................................................... 3
5. SWITCHGEAR - SURGE ARRESTER ............................................................................ 4

SECTION: SWITCHGEAR (FOR BESS), REV 00 1

 SWITCHGEAR
(for Battery Energy Storage System)

1. GENERAL

The Circuit Breakers, Instrument Transformers, Isolators & Earth Switch, Surge Arresters shall
be designed for use in the geographic and meteorological conditions as given in Section-
Project.

2. SWITCHGEAR - CIRCUIT BREAKER (CB)

The circuit breakers and accessories shall conform to IEC: 62271-100, IEC: 62271-1 and other
relevant IEC standards and shall also be in accordance with requirements specified in Section-
GTR. The circuit breaker shall be complete with operating mechanism, common marshalling
box, piping, inter-pole cables, cable accessories like glands, terminal blocks, marking ferrules,
lugs, pressure gauges, density monitors (with graduated scale), galvanised support structure,
platform with ladder for CB, foundation bolts and all other accessories required for carrying
out all the functions of the CB (as applicable based on voltage level & manufacturer design).
All necessary parts to provide a complete and operable circuit breaker installation such as
terminal pads, control parts and other devices shall be provided. Painting shall be done in line
with Section – GTR. The support structure, platform & ladder of circuit breaker shall be hot
dip galvanised. Exposed hardware items shall be hot dip galvanised or Electro-galvanised.

For Circuit Breakers, voltage level, nominal current rating, short circuit withstand capability
etc. shall be finalized during detailed engineering. All porcelain & polymer hollow column
insulators (as applicable) shall conform to IEC-62155 & IEC-61462 respectively. In
accordance with the requirements stipulated under Section-GTR the circuit breaker along with
its operating mechanism shall conform to the type tests & routine tests requirement as per IEC:
62271-100 & test reports shall be submitted for the Employer’s review.

3. SWITCHGEAR-INSTRUMENT TRANSFORMERS

The instrument transformers and accessories shall conform to the latest version of the standards
specified below and shall be in accordance with the requirements in Section-GTR.
i. Current Transformers (CT): IEC: 61869-1 & 61869-2 or IS: 2705 Part-1 to 4.
ii. Capacitive Voltage Transformers (CVT): IEC: 61869-1, 61869-5 & IEC-60358 or IS-3156
Part-1 to 4.
iii. Inductive Voltage Transformers (IVT): IEC: 61869-1 & 61869-3 or IS-3156 Part-1 to 3.

Instruments transformers shall be hermetically sealed units. Polarity marks shall indelibly be
marked on each instrument transformer and at the lead terminals at the associated terminal

SECTION: SWITCHGEAR (FOR BESS), REV 00 2

block. The instrument transformers shall be complete with its terminal box and a common
marshalling box for a set of 3 instrument transformers. The external surface of instrument
transformer, if made of steel, shall be hot dip galvanized or painted as per Section-GTR.
External surface of aluminium can have natural finish. For all instrument transformers, voltage
level, nominal current rating, short circuit withstand capability, Secondary side number of
cores, ratio, burden, accuracy class etc. shall be finalized during detailed engineering. In
accordance with the requirements in Section-GTR, Current Transformer and Voltage
Transformer should have been type tested and shall be subjected to routine tests in accordance
with relevant IEC. The test reports of type tests, as applicable, as per IEC-61869-2 for CT,
IEC-61869-5/IEC-60358 for CVT, and IEC-61869-3 for IVT shall be submitted for the
Employer’s review.

4. SWITCHGEAR – ISOLATOR

The Isolators and accessories shall conform in general to IS/ IEC: 62271-102 latest edition and
shall be in accordance with requirement of Section-GTR. Complete isolator with all the
necessary items for successful operation shall be supplied including but not limited to the
following:
i. Isolator with complete Support Insulators, operating rod insulator, base frame, linkages,
operating mechanism, control cabinet, interlock etc.
ii. All necessary parts to provide a complete and operable isolator installation, control parts
and other devices whether specifically called for herein or not.
Isolators and earth switches shall be capable of withstanding the dynamic and thermal effects
of the rated short circuit current of the systems in their closed position. They shall be
constructed such that they do not open under influence of short circuit current.
The earth switches, wherever provided, shall be constructionally interlocked so that the earth
switches can be operated only when the isolator is open and vice versa. The constructional
interlocks shall be built in construction of isolator and shall be in addition to the electrical
interlocks. The interlocking coil shall be suitable for continuous operation from station DC
supply and within a variation range as stipulated in Section-GTR. The earthing switches shall
be capable of discharging trapped charges of the associated lines/ sections. For Isolators,
voltage level, nominal current rating, short circuit withstand capability etc. shall be finalized
during detailed engineering.
The insulator shall conform to IS: 2544, IEC-60168 and IEC-60815. The porcelain of the
insulator shall conform to the requirements stipulated under Section-GTR. The earthing
switches shall form an integral part of the isolator and shall be mounted on the base frame of
the isolator. Earthing switches shall be only locally operated. Each earth switch shall be
provided with flexible copper/aluminium braids for connection to earth terminal. These braids
shall have the same short time current carrying capacity as the earth blade. The earth switch
should be able to carry the same fault current as the main blades of the Isolators and shall
withstand dynamic stresses.
In continuation to the requirements stipulated under Section-GTR the isolator along with its
earthing switch and operating mechanism should be type tested as per IEC/IS and shall be

SECTION: SWITCHGEAR (FOR BESS), REV 00 3

subjected to routine tests in accordance with latest edition of IEC-62271-102. The test reports
of the type tests as per latest IS/IEC 62271-102 shall also be submitted for the Employer’s
review.

5. SWITCHGEAR - SURGE ARRESTER

The Surge arresters shall conform to IS 15086 part 4/IEC: 60099-4 (latest edition) shall also be
in accordance with requirements under Section -GTR.
The surge arresters shall be of Station High Duty (SH) / Station Medium Duty (SM) / Station
Low Duty (SL) as per requirement and gapless type without any series or shunt gaps.
The non-linear blocks shall be of sintered metal oxide material. These shall be provided in such
a way as to obtain robust construction, with excellent mechanical and electrical properties even
after repeated operations. Arresters shall be of hermetically sealed units, self-supporting
construction. For Surge Arresters, rated voltage, continuous operating voltage, nominal
discharge current, maximum residual voltage at nominal discharge current etc. shall be
finalized during detailed engineering.
Arresters shall be complete with insulating base having provision for bolting to flat surface of
structure. Self-contained discharge counters, suitably enclosed for outdoor use and requiring
no auxiliary or battery supply for operation shall be provided for each single pole unit along
with necessary connection arrangement. Suitable leakage current meters should also be
provided. Surge monitor consisting of discharge counters and milliammeters should be suitable
to be mounted on support structure of the arrester and should be tested for IP66 degree of
protection (for outdoor applications).

All routine tests shall be conducted on the hollow column insulators as per IEC 62155. Polymer
housing shall be tested in accordance to IEC-61462. In accordance with the requirements
stipulated under Section-GTR, the surge arresters should have been type tested as per latest
IEC/IS and shall be subjected to routine and acceptance tests in accordance with latest IEC/IS.
Test reports for all type tests as per latest IS 15086 part4/IEC-60099-4 shall also be submitted
for the Employer’s review.
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SECTION: SWITCHGEAR (FOR BESS), REV 00 4