A 500kV AIS Switchyard Rejuvenation in British Columbia using Hybrids

Transcription

1 A 500kV AIS Switchyard Rejuvenation in British Columbia using Hybrids Author Company Presenter T.A. Messinger BC Hydro E. Burt BC Hydro P.Glaubitz Siemens AG

2 2 Built: In early 1970 s The Ingledow 500kV Substation One of the most important substations in BC Hydro system - Before rejuvenation Layout: Three AIS switchyards, 10-bays ring, 1 1/3 circuit breaker arrangement System: Five incoming 500kV lines, including two connections with WECC via Bonneville Power Authority Three 500/230kV, 1200MVA power transformers connecting to 230kV switchyard and nine 230kV lines serving Lower Mainland Airblast breakers and associated oil-filled CT s and air-insulated disconnectors Containing: Airblast breakers multiple interrupting chambers (6-8) and closing resistors but not suitable for local seismic withstand requirements Rated for 50kA, 2000/3000A (depending on elements) Airblast CB s at Ingledow

3 3 The Ingledow 500kV Substation (cont d) System Planning requirements were inching towards 63kA, 4000A By early 2000 reliability decreasing, including one explosive failure of an airblast breaker and one oil-filled CT explosive failure with damages to adjacent equipment. -T MB2 5 HDN 6 -T5 BPA -T2 CGE CB ABB CB NTC KLY BPA 8 4 5MB1 Ingledow 500 kv existing 1 1/3 Circuit Breaker arrangement

4 4 Switching requirements: Updating Requirements The requirements for new switchyard outlined: o 50kA fault current capability, 4000A continuous rating, 1550kV LIL, 1350kV TRV, equipped with spring/spring operating mechanisms o No closing resistors (using POW switching and high energy absorption SA s) Other requirements: o High seismic withstand o Oil-less CT s and Polymeric-type bushings and insulators o Internal arc-resistance withstand of all electrical equipment o Decommissioning of maintenance- intensive air pressure stations

5 5 Search for Optimal Solutions Options to replace existing switching bays: 1 New LT SF 6 breakers, associated SF 6 CT s and new air-insulated disconnect switches 2 New DT SF 6 breakers and new air-insulated disconnectors 3 New SF 6 Hybrids with integrated SF 6 -insulated CT s, disconnector and earthing switches in essence 1-bay GIS units 4 Replacement using Gas Insulated Switchgear (GIS) Extensive evaluation indicated Option 3 as most advantageous. A blanket order was tendered, evaluated and awarded for 500kV hybrids meeting the specification.

6 6 The Options Evaluation Objectives Minimizing life cycle cost Minimize reliability risk Maximize equipment availability Collateral Damage and Safety Risk Measures Expected net present value 1. Live Tank with free standing CT s and air insulated switches 2. Dead tank with bushing CT s and air insulated switches. 3. Hybrids with integrated SF 6 - insulated CT s, disconnect and ground switches high medium low Relative value Relative value Relative value ,2,3: ranking

7 Project Execution Several issues had to be resolved with equipment manufacturer: Drawings approvals delayed due to IEC standards used by manufacture versus IEEE standards used by BC Hydro The seismic test had to be repeated due to wrong bushings used Delay in the development of the POW controller due to misunderstanding of BC Hydro requirements Several crates on first shipment were damaged resulting in water ingress though no damage to equipment Post-installation, a couple of bushings developed small SF 6 gas leaks, due to irregularities in subsupplier QA issues were resolved. Construction contract was tendered on cost + bases and first outage expected to last 8 weeks o Cost greatly exceeded the estimates and outage lasted 16 weeks Following that BC Hydro negotiated a turn-key installation contract with equipment manufacturer, resulting in successful and uneventful completion of the project. 7

8 8 Advantages and Limitations of Hybrid Solutions Advantages of the Hybrid Solution Significantly smaller footprint for the bay Improved safety as fewer energised elements are exposed Improved overall reliability of the bay Faster installation and commissioning time Extended life time Low life cycle costs Limitations of the Hybrid Solution Decreased flexibility in case of a subcomponent failure compared to AIS/stand alone equipment Temperature limitations to -30 C without additional measures Base frame positioning for first pole Hybrid undergoing commissioning testing

9 9 CONCLUSION While the project took longer than original schedule, it was mainly due to difficulties to obtain 10 weeks outages, in particular during the winter and summer periods. Using the equipment manufacturer as turn-key project manager made the difference between success and possibly failure Coordination between the project manager and utility is critical and worked very well in this case.

10 10 Ingledow 500kV Switchyard The Replacement Project at Ingledow sub was a success

11 11 Thank you very much for your attention! Toly Messinger BC Hydro Vancouver, Canada Ed Burt BC Hydro Vancouver, Canada Peter Glaubitz Siemens AG Erlangen, Germany