General Electric Company

Electric Power Research Institute Incorporated

Electric Power Research Limited

Kara Clark

Einar Vaughn Larsen

Nicholas Wright Miller

Reigh Allen Walling

Mark Edward Cardinal

Carl A Wegner

Richard J Piwko

Andreas Kirchner

Anthony William Galbraith

Owen Jannis Schelenz

Murray A Eitzmann

Josef Urbanek

Sandeep Nyati

J Kenneth Hooker

Power inverters are controlled in response to reactive power support commands received from a power grid such that at least one power inverter provides reactive power to the power grid. The reactive power provided is based on each power inverter's reactive power capacity only while the total power capacity of each power inverter providing the reactive power is not exhausted in generating real power.

System and method for distribution of inverter VAR support

A voltage control arrangement for a system of multiple windfarms with transmission lines. Voltage is regulated at a point of regulation on the system, such as a high voltage substation or other system bus. Regulation is achieved at the point of regulation by sensing the voltage, comparing to a reference voltage, and adjusting the reactive power output of the wind turbines and other equipment in the system. The regulation point may be shifted to another point if needed to respect voltage limits at that points of the system after attempting to shift reactive load to restore voltage within limits at the other points in the system. The reference voltage may be adjusted to minimize losses for the system of multiple windfarms and transmission lines. A loss optimizing algorithm is applied to the combined multiple windfarm and transmission line to shift reactive load among local windfarms to minimize losses and to shift reactive load among individual wind turbines within an individual windfarm.

Optimizing system loss for a system of multiple windfarms

Voltage control at windfarms

An automatic generation control (AGC) augmentation system and method for wind power plant integration for controlling the power contribution to a grid by the wind plant is disclosed that provides for the calculation of the area control error (ACE) by actively communicating to the wind plant ramp rate limits and curtailment requests contributing to the ACE calculation. The augmented control of the ACE minimizes the amount of lost energy production by the wind plant.

Automatic generation control augmentation for wind plant integration

A wind turbine generator control system is provided for controlling output of a plurality of tightly-coupled windfarms connected at a point of common coupling with a power system grid. A master reactive control device employs algorithms whose technical effect is to coordinate the real power, reactive power and voltage output of the multiple windfarms. The controller incorporates a reactive power regulator that can be used to regulate reactive power, power factor or voltage at the point of common coupling and an active power regulator that can be used to regulate real power at the point of common coupling; such that each windfarm is not asked to contribute or violate its own operating capability.

Intra-area master reactive controller for tightly coupled windfarms

A power generation system including a wind turbine generator for generating electrical power, an alternate power source, and a processor programmed to control operation of the alternate power source to control a power output of the alternate power source at least partially based on at least one of a wind parameter, a wind forecast, a wind turbine condition sensor, and a power output of the electrical generator.

Methods and systems for generating electrical power

A static series voltage regulator (SSVR) for an electric power distribution system protects a load on a feeder branch from voltage dips by boosting voltage under certain conditions. The SSVR contains a 3-phase voltage source inverter and a source bridge, fed from a source, supplying the dc side of the inverter. A series transformer is connected between the power source and a load coupling the inverter output to appear between the power source and the load. A surge filter connected in parallel with the series transformer protects the load from fast front voltage pulses produced by the inverter, and isolation and bypass switches isolate the inverter and series transformer from the power source and load. The inverter is controlled so that during normal operation it acts as a short on the series transformer, and, during a fault that causes a dip in the source voltage, it injects voltage in series with the source voltage to provide a boost action to maintain load voltage at a desired magnitude and balance. The SSVR senses the incoming voltage from the utility and load current and constructs what the load voltage would be in the absence of boost action. This information is processed through a minimum detector to obtain a signal V,which rapidly responds to a voltage dip but remembers a dip happened for a few cycles. When V,falls below some threshold then boosting begins to bring load voltage to a desired level. Boosting is halted after V,exceeds the threshold, or when the load voltage exceeds a high voltage threshold.

Static series voltage regulator

An overload management system is provided, including a method and an apparatus, for controlling the operation of electrical equipment in a short-term overload region above the equipment's continuous capability operation curve, without suffering significant loss of equipment life. This overload management system is particularly beneficial for use with equipment having load management capability, such as a modular thyristor controlled series capacitor (TCSC) system using phase controlled firing based on monitored capacitor voltage and line current. For vernier operation, the system predicts an upcoming firing angle for switching a switching device to govern the current received by the electrical device, such as to bypass line current around a series capacitor of the TCSC system. The overload management system may serve as one of several higher-level controllers providing input to a vernier controller for accommodating competing objectives of various system demands.

Overload management system

A modular thyristor controlled series capacitor (TCSC) system, including a method and apparatus, uses phase controlled firing based on monitored capacitor voltage and line current. For vernier operation, the TCSC system predicts an upcoming firing angle for switching a thyristor controlled commutating circuit to bypass line current around a series capacitor. Each bypass current pulse changes the capacitor voltage proportionally to the integrated value of the current pulse. The TCSC system promptly responds to an offset command from a higher-level controller to control bypass thyristor duty to minimize thyristor damage, and to prevent capacitor voltage drift during line current disturbances. In a multi-module TCSC system, the higher level controller accommodates competing objectives of various system demands, including minimizing losses in scheduling control, stabilizing transients, damping subsynchronous resonance (SSR) oscillations, damping direct current (DC) offset, and damping power-swings.

Modular thyristor controlled series capacitor control system

A thyristor controlled series capacitor (TCSC) system, including a method and apparatus, uses phase controlled firing based on monitored capacitor voltage and line current. For vernier operation, the TCSC system predicts an upcoming firing angle for switching a thyristor controlled commutating circuit to bypass line current around a series capacitor. Each bypass current pulse changes the capacitor voltage proportionally to the integrated value of the current pulse. To damp the natural oscillatory response of the inductive commutating circuit and the capacitor, a bypass mode firing angle is introduced to create a nonlinear response. The harmonic distortion on the commutating circuit current waveform is determined from the capacitor voltage, which is then used to determine the magnitude of the firing angle. Preferably the firing angle magnitude decreases in response to decreasing capacitor voltage, eventually returning to steady-state conditions.

Transient damping thyristor controlled series capacitor system

A firing control scheme, including a method and apparatus, for secure vernier operation of a thyristor controlled series capacitor (TCSC) in series with a transmission line uses phase controlled firing based on monitored capacitor voltage and line current. The TCSC system has a thyristor switched inductive commutating circuit in parallel with the series capacitor. Vernier operation of the TCSC system is provided by predicting an upcoming firing angle for switching the commutating circuit to conduct a thyristor bypass current pulse therethrough. The current pulse causes an alternating offset component of voltage to appear across the series capacitor, in addition to the normal voltage component. Each current pulse changes the capacitor voltage proportionally to the integrated value of the current pulse. The TCSC system promptly responds to an offset command from a higher-level controller, precisely controls the duty on the bypass thyristors to minimize thyristor damage, and prevents drift of the capacitor voltage away from a desired setting during line current disturbances.

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Glenville, NY, United States of America

Kara Clark