O&M – Business: Osprey Energy Center
Generator AVR O&M improvements
Osprey Energy Center
Calpine Corp
600-MW, gas-fired, 2 × 1 combined cycle located in Auburndale, Fla
Plant manager: Steve Smith
Key project participants: Gil Kaelin, maintenance manager;Roy Price, lead IC&E technician; Mike Stracener, IC&E technician; Tim Dougherty, IC&E technician
Challenge.
Limited indications and knowledge of status on generator automatic voltage regulators (AVR) can hinder NERC compliance.
Solution.
With a specific focus on NERC compliance, the site examined AVR reliability and mode-of-operation indicators available to operating personnel. Improvements were made in the following areas:
- Review relay outputs that were configured, but not installed, for DCS monitoring.
- Actualize the configured relays to the DCS to give an accurate indication of AVR status.
- In the case of this particular AVR, the unit can perform an “emergency switch to manual” yet still indicate “auto on.” Investigation revealed several additional relay outputs from the AVR that could be brought to the DCS for more indication.
- AVR power supply caused interference with receiver boards for diode status transmitters. A changing magnetic field in the proximity of the receiver board caused a change in diode-status indication. The measured magnetic field with the unit at speed an un-excited reading is 0.11 Tesla and when fully excited it is 0.25 T to 0.45T. The receiver board was moved to an enclosure with no changing magnetic field and the problem was solved.
- Alarm indications for receiver boards, voltage regulators, and AVR mode indications were placed on a single screen to give operators single screen view (Fig 103).
- The operating environment for the steam turbine/generator AVR was moved to a climate- controlled building to provide greater life of the components.
- A semi-annual PM to test alarm outputs to the DCS was implemented to ensure alarm indicators are functional.
- I&E personnel established a quick reference guide for local troubleshooting of the AVRs by non-technical personnel to help identify and correct problems during callout transitions.
Results.
Fully configuring generator AVRs to the plant’s digital control system increases operator control and monitoring capability while effectively maintaining NERC compliance.
