An attempt is made in This work to present critical literature review and an up-to-date and exhaustive bibliography on the AGC of power systems. Various control aspects concerning the AGC problem have been highlighted. AGC schemes based on parameters, such as linear and nonlinear power system models, classical and optimal control, and centralized, decentralized, and multilevel control, are discussed. AGC strategies based on digital, self-tuning control, adaptive, VSS systems, and intelligent/soft computing control have been included. Finally, the investigations on AGC systems incorporating BES/SMES, wind turbines, FACTS devices, and PV systems have also been discussed.

Recent philosophies of automatic generation control strategies in power systems

This two-part paper surveys the frequency and voltage control ancillary services in power systems from various parts of the world. In this second part, essential economic features that must be taken into account when designing markets for ancillary services are first discussed. The methods adopted in eight different systems (Australia, France, Germany, Great Britain, New Zealand, PJM, Spain, and Sweden) for trading frequency and voltage control ancillary services are then compared. Lastly, new indicators for comparing volumes and costs of ancillary services across systems are proposed and calculated for the systems included in this survey. The companion paper surveys the technical features of these ancillary services

A Survey of Frequency and Voltage Control Ancillary Services—Part I: Technical Features

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Doubly fed induction generators (DFIGs), often organized in wind parks, are the most important generators used for variable-speed wind energy generation. This paper reviews the control systems for the operation of DFIGs and brushless DFIGs in wind energy applications. Control systems for stand-alone operation, connection to balanced or unbalanced grids, sensorless control, and frequency support from DFIGs and low-voltage ride-through issues are discussed.

Overview of Control Systems for the Operation of DFIGs in Wind Energy Applications

In this paper an extensive literature review on load–frequency control (LFC) problem in power system has been highlighted. The various configuration of power system models and control techniques/strategies that concerns to LFC issues have been addressed in conventional as well as distribution generation-based power systems. Further, investigations on LFC challenges incorporating storage devices BESS/SMES, FACTS devices, wind–diesel and PV systems etc have been discussed too.

A literature survey on load–frequency control for conventional and distribution generation power systems

Utilities use operating reserve to cope with the disturbances. To ensure that the operating frequency and system security are well maintained, the operating guidelines always specify that the reserve quantity and response rate should meet some prescribed levels. This paper proposes methodologies to evaluate system's frequency response characteristic (beta) and operating reserve for the isolated power system. With the presented algorithm to estimate system's beta online, a real-time allocation of operating reserve would be feasible to meet the guidelines for either regulation or contingency operation. Test results from the simulated conditions, and from the actual operating data verify the merits of the proposed methodologies to system's frequency control, and reliability.

An Online Approach to Allocate Operating Reserve for an Isolated Power System

Utilities use contingency reserves to deal with the contingency events. To ensure that the reliability and operating frequency are well maintained, the reserve scheduling guidelines always specify that the reserve quantity and response rate should meet some precise levels. This paper presents an algorithm to estimate the frequency response characteristic, beta, of an isolated system online. The real-time estimated beta could be gainfully used for the instant when the update of reserve scheduling is needed. A contingency reserve scheduling according to a series of frequency restoration processes is also proposed to ensure the effectiveness of the reserve response. Test results showing that the scheduling method in simulated conditions, and on actual operating data, was confirmed to be feasible to ensure the power system's reliability

A Real-Time Contingency Reserve Scheduling for an Isolated Power System

Summary form only given. With the increasing wind penetration into the power system, the guidelines of operating reserve need to be revised to ensure system security. Due to the uncertain characteristics of the wind production, the general way of the reserve management for wind integration is to provide additional reserve margin by conventional plants. Such a strategy could not only increase the operating costs but also impose additional unit stress during the frequency event. This paper presents a strategy that incorporates doubly-fed induction generator (DFIG) wind farms to actively provide primary reserve for frequency control. The wind reserve allocation according to available wind speed is proposed. An integrated system that consists of the traditional units and DFIG wind farms has been developed to assess the frequency response and generating interactions. Simulation results are discussed to illustrate the superiority of the presented strategy in reserve operation.

Dynamic reserve allocation for system contingency by DFIG wind farms

In this paper, a digitally controlled Single Input Dual Output (SIDO) buck converter with Phase Sequence Interchange (PSI) scheme for reducing transient cross-regulation is proposed. The PSI scheme is especially designed to solve cross-regulation problem that is usually seen when load steps up in a voltage-mode SIDO buck converter operating in continuous conduction mode (CCM). In addition, a discharging path is employed to reduce cross-regulation during load drop. The digital control of the proposed scheme is implemented and verified by the FPGA. Experimental results show that the suppression of the cross-regulation is comparable to the other state-of-the-art.

Digitally controlled low cross-regulation single-inductor dual-output (SIDO) buck converter

This paper describes the refinements of an ACE model to improve its accuracy, the results of tests conducted on field data of its accuracy, and of its use in decomposing the 1-min average of ACE of a control area to identify the regulation burden associated to certain widely varying loads.

Le-Ren Chang-Chien

Papers

An Online Approach to Allocate Operating Reserve for an Isolated Power System

A Real-Time Contingency Reserve Scheduling for an Isolated Power System

Dynamic reserve allocation for system contingency by DFIG wind farms

Digitally controlled low cross-regulation single-inductor dual-output (SIDO) buck converter

Field tests and refinements of an ACE model