As background, we describe frequently used feedforward wide-area discontinuous power system stability controls. Then we describe online demonstration of a new response-based (feedback) Wide-Area stability and voltage Control System (WACS). The control system uses powerful discontinuous actions for power system stabilization. The control system comprises phasor measurements at many substations, fiber-optic communications, real-time deterministic computers, and transfer trip output signals to circuit breakers at many other substations and power plants. Finally, we describe future development of WACS. WACS is developed as a flexible platform to prevent blackouts and facilitate electrical commerce.

WACS-Wide-Area Stability and Voltage Control System: R&D and Online Demonstration

This paper aims at investigating the effect of the coordination of fuzzy logic-controlled superconducting magnetic energy storage (SMES) and optimal reclosing on the transient stability in a simulated multi-machine power system during unsuccessful reclosing of circuit breakers. The performance of the coordinated operation of fuzzy logic-controlled SMES and optimal reclosing is compared to that of the coordinated operation of fuzzy logic-controlled SMES and conventional auto-reclosing. Also, the performance of the fuzzy logic-controlled SMES is compared to that of an alternative static nonlinear controlled SMES. The control scheme of SMES is based on a pulse width modulation (PWM) voltage source converter (VSC) and a two-quadrant dc-dc chopper using gate-turn-off (GTO) thyristor. The parameters of the proposed fuzzy logic controller are optimally tuned by the genetic algorithm (GA) method. Simulation results of both balanced and unbalanced faults at different points in a multi-machine power system show that the coordinated operation of fuzzy controlled SMES and optimal reclosing is able to stabilize the system well in case of an unsuccessful reclosing. Moreover, the transient stability performance of the coordinated operation of fuzzy controlled SMES and optimal reclosing is better than that of the coordinated operation of fuzzy controlled SMES and conventional auto-reclosing. Also, the performance of the fuzzy logic-controlled SMES is better than that of the static nonlinear controlled SMES.

Transient Stability Enhancement by Fuzzy Logic-Controlled SMES Considering Coordination With Optimal Reclosing of Circuit Breakers

Summary form only given. As background, we describe frequently used feedforward wide-area power system stability controls. Then we describe on-line demonstration of a new response-based (feedback) wide-area stability and voltage control system (WACS). The control system uses powerful discontinuous actions for power system stabilization. The control system comprises phasor measurements at many substations, fiber optic communications, real-time deterministic computers, and transfer trip output signals to circuit breakers at many other substations and power plants. Finally, we describe future development of WACS. WACS is developed as a flexible platform to prevent blackouts and facilitate electrical commerce.

WACS-wide-area stability and voltage control system: R&D and on-line demonstration

A new monitoring method based on a wide-area network of Phaser Measurement Units (PMU) is proposed. This tool detects on-line and in real-time an incipient voltage instability in the power system. A geographical visualization is introduced to monitor efficiently the state of the network. The method is general and can be implemented in any part of a network prone to voltage instability. It can be used to trigger corrective actions to avoid a collapse. The hypotheses and the results of the new method will be discussed in regard with those given by the Thevenin's equivalent computed at the load bus.

Voltage-Stability Monitoring Using Wide-Area Measurement Systems

Effects of electricity-price policy on electricity demand and manufacturing output

Large-scale blackout risk is greatly reduced by multiple layers of defense. With best practices for tree trimming, power system planning and design, control center operation, prioritized control and protection up- grades, automatic load shedding, special protection sys- tems, etc., blackout risk becomes very low. Wide-area feedback control for discontinuous actions such as genera- tor or load tripping and capacitor/reactor bank switching, is an advanced "special protection system." After reviewing blackouts and close calls in 1996, 1999, 2003, and 2004, we describe Bonneville Power Administra- tion (BPA) development and on-line demonstration of Wide-Area stability and voltage Control System (WACS). WACS uses phasor measurements from many stations as inputs, with existing special protection system transfer trip circuits available for outputs. We describe in detail WACS response and validation for the June 14, 2004 outage of 4600 MW of generation near Phoenix, Arizona.

Robert E. Wilson

Papers

Reducing blackout risk by a wide-area control system (wacs): adding a new layer of defense