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COMMENTS ON PROTECTION SLD OF BARAPUKURIA 230/132Kv substation
General Comments:
Sl no. Comments of PGCB Energypac Answers
1. CT sizing calculations have to be submitted separately for approval Agreed will be submitted
of CT ratings will not be issued without the sizing calculation. later.
2. As per the SLD, it seems that both line differential relays are located For each line 2Nos. Line
at the same panel and CT Secondary wire be extended from the differential relay 7SD87
power plant end to the substation end. CT capability of handling the as main-1 & main-2 to
increased burden needs to be calculated in such situation. But it is be installed at PGCB
recommend to install line differential relay in separate ends &BPDB end. Both relays
shall be communicated
with each other by fiber
optic cable.
3. All relay setting calculation needs to be performed by simulation Relay setting calculation
software and have to be approved by PGCB. shall be done manually.
4. Tariff metering scheme should be approved by BPD Agreed
5. Only one energy meter is shown for each feeder; the issue to be 2 Nos terrif meter shall
decided by SSD & QC with reference to the contract. be installed at line.
6. Necessary NLDC integration have to be performed by EPC As per contract.
contractor.
7. Bus bar Protection is not shown for 230kV Bus bar in the PSLD. As Out of scope (No need at
per the practice of PGCB, all 230kV substations should be equipped this moment as
with bus bar protection along with breaker failure protection. It is discussed with PGCB
recommended to take necessary steps for including BBP in the Design & Protection
mentioned substation. Department)
8. Only one main protection relay is shown for each 230kV line. As per As discussed with PGCB
the practice of PGCB and Bangladesh Grid Code, all 230kV lines for protection of 230KV
should be equipped with Main-1 and Main-2 protection line, 2 Nos. line
Relays. One more set of line differential relay has to be provided for differential relay as
each line. The relays may be Supplied from the store of PGCB as Main-1 & Main-2 is
required; necessary design, installation, testing and Commissioning required. These 2 Nos.
works have to be done by the contractor. of relay will be supplied
by PGCB. Type of relay is
7SD87 of SIEMENS.
PGCB shall help
ENERGYPAC to co-
ordinate with BPDB for
installation of
differential relay at
230KV P/S end.
9. All relays must be provided with necessary Test Terminal Blocks Agreed
(TTB) in the respective panel.
10. No 33kV CB is shown between T-03 and associated earthing Out of scope (Omitted
transformer. 33kV CB should be provided between the transformers from SLD)
11. CT of 0.415kV side is used in Transformer overall differential relay of Out of scope (Omitted
T-03; it is recommended To use CT for 33kV side of the earthing from SLD)
transformer instead
12. REF protections have to be available for T-03 as well as its earting Out of scope (Omitted
transformer in the Main-1tramsformer differential relay. REF from SLD)
protection of earthing transformer will cover the 33kV side And its
neutral part.
13. Over-current and earth fault protection need to be provided for N/A
33kV side as well as 0.415kVSide of the earthing transformer.
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14. Synchrocheck functions have to be activated for both 230k V and N/A as discussed with
132kV side CB of the Transformer. PGCB Design &
Protection Department.
15. No overall differential protection is provided for T02. It is (Out of scope) PGCB will
recommended to provided overall differential protection for the supply 1 No. differential
transformer covering the post CTs. The relay may supplied from the relay type 7UT86 of
store of PGCB as required; necessary design, installation, testing and SIEMENS. ENERGYPAC
commissioning works have to be done by the contractor. will do the installation
works for T-02
transformer.
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