Saudi Arabia, Al Madi-nah

1. Site Location: Yanbu

Plant Description:

Yanbu Export Refinery Project is fed via 380kV, 4 km double circuit underground cables, from the 380kV 1.5 breaker GIS substation.

380kV incomers are connected to 380kV double bus GIS substation SS01.  Substation SS01 comprises feeds to six 380kV/34.5kV/34.5kV transformers, two future extensions and a bus coupler.  Six 34.5kV-outgoing feeders, each approximately 2 km long, connect to double bus GIS substations SS02, SS03 and SS04 via underground cables.  Each 380kV underground feeder from 380kV 1.5 breaker GIS substation is designed to carry the total plant load.

Each of the substations, SS02, SS03 and SS04 comprises two incomers, a bus coupler and a number of outgoing feeders.  Each 34.5kV underground feeder from SS01 is designed to carry the total plant load of individual 34.5kV substation.

For SS01, power system protection comprises Main 1 & 2 and Back-up 1 & 2 for incoming cables, transformer feeders, busbars, breaker fail, bus couplers, transformers and 34.5kV outgoing cables.  All protection relays are of manufacturers Alstom, ABB and Schweitzer.

For SS02, SS03 and SS04, power system protection comprises Main and Back-up protection for incoming cables, busbars, breaker fail, bus couplers and outgoing cables.  All protection relays are of manufacturers Alstom and Schweitzer.


Scope of Work:

1) To carry out a design review to assess protection and design requirements for 380kV and 34.5kV GIS Sub-stations SS01, SS02, SS03 and SS04.

2) To carry out CT & VT calculations to verify minimum requirement for CTs & VTs as per ANSI Standard and relay manufacturer guidelines as required.

3) To carry out a Short Circuit Study to recommend relay settings to address the directional and non-directional Over-current and Earth Fault protection co-ordination.

4) To produce Setting Schedules for Main 1 & 2 and Back-up 1 & 2 protections for SS01, SS02, SS03 & SS04.

5) To carry out pre-commissioning and commissioning of 380kV and 34.5kV GIS Sub-stations SS01, SS02, SS03 and SS04.

6) To provide on site technical support, protection consultancy, project co-ordination and perform testing & commissioning activities as required.

7) To examine causes of 380kV/34.5kV/34.5kV, YN1yn0d11, transformer earth fault protection, 51N, trips during initial energisation and prepare a detailed report with explanation of causes and the solution implemented to avaoid this problem in future.