Pakistan, Sindh

1. Site Location: Lasmo Oil Bhit Field, nr Sehwin sharif, Dadu, Sindh

Plant Description: The power system at Bhit Field is supplied entirely by three on-site gas turbine generators, each rated at 23.5 MW, 0.8 pf at design air ambient temperature of 43.3 °C. The generation is at 11 kV / 50 Hz, connected directly to the 11 kV main switchboard. The main switchboard supplies two 12.4 MW compressor units at 11 kV, and also feeds the 3.3 kV and 415 V switchboards. An emergency diesel generator set rated at 1825 kW is available on the 3.3 kV switchboard, which will normally feed only part of the 3.3 kV and 415 V systems.

Scope of Work:

Job 1) To address the protection co-ordination of the network from the main generators through to the MV switchboards, transformers, LV switchboards and distribution boards, and to include calculations and curves for all protection devices and current transformers, demonstrating that discrimination is achieved. Short circuit, load flow, transient stability and motor starting studies were also conducted.

Job 2) To carry out a study of the electrical system, which included new electrical loads specified by the client, as well as updated ratings for existing loads. This revision is to be based on the previously existing studies conducted by PEC for Costain and Alstom DSL, and includes simulations for load flow, short circuit, motor starting and transient stability. The protection settings on the 11 kV, 3.3 kV and 415 V switchboards are also analysed, according to the maximum and minimum fault levels. The new plant for Phase 2 is a Third By-Pass Train that was incorporated into the existing Gas Compressor Plant.


2. Site Location: Karachi

Plant Description: Tornado gas turbine with a UNIPAK 6.6 kV, 50 Hz, 7.2 MVA machine.

Scope of Work: The generator is the sole HV supply on site. The scope of work was to commission the generator to run in island mode operation, and to commission the generator circuit breaker.