Generator testing of hydro-power plants in the pacific northwest: impact on system studies

摘要

The Corps of Engineers (COE) is operating major hydro power projects in the Pacific Northwest, including Columbia-River plants such as Chief Joseph (2614 MW), John Day (2158 MW), The Dalles (2080 MW), McNary (1120 MW), and Bonneville (1224 MW).Dynamic behavior of these plants has significant impact on stability of the entire WSCC system, as demonstrated by the August 10, 1996 WSCC system outage. Therefore, correct modeling of these generators is necessary in planning studies for determiningsafe stability limits and establishing operating nomograms.General observations of the COE generator testing are:1. Machine data is generally adequate.2. Voltage regulators and exciters are more responsive than previously modeled. Excitation gains are typically higher than previously modeled.3. Hydro plants are equipped with Reactive Current Droop Compensation (RCC) to ensure stable operation of paralleled (bussed together) generators. RCC was not previously modeled in transient stability studies nor in post-transient analysis.4. Power System Stabilizers are less effective than previously modeled. The problems are mostly hardware-related, when high noisy transducers prevent high P55 gains. Many stabilizers have excessive washout time constants of 30 seconds.The objective of this investigation is to evaluate impact of new data on system studies: voltage support, first swing stability, and power oscillations damping.