基于系统状态分级与CSMA/CD机制的微电网自治控制策略研究

A Decentralized Control in Microgrid: An Autonomous Control Strategy Derived from CSMA/CD Mechanism

摘要: 针对微电网中多源协调控制问题，提出了一种不基于中心控制器(MGCC)和通信的多源自治控制策略，该策略主要包含基于系统状态分级的微电网自治策略和基于CSMA/CD机制的微源调节策略两套子策略。分级调节策略建立了系统状态分级模型评估系统运行状态，不同状态级别下微源的控制策略不同，从系统层面上优化了各单元运行状态；分时调节策略以CSMA/CD竞争机制为核心，量化了各CMG参与系统调节优先级高低，使微源调节变得有序，保证主电源的唯一性。应对微网状态变化时，该自治控制策略可以从分布式电源中选取一个最优调节电源(MDG)，从而有效的解决了多源并联运行采用VF或下垂控制时的系统环流问题，提高了系统稳定性。利用PSCAD/EMTDC软件建立了仿真系统，验证了所提控制策略的有效性。

Abstract: In this paper, aiming at solving multi-source coordination control problem in micro-grid, an autonomous control strategy which is not based on central controller (MGCC) and on communica-tion has been proposed. This strategy mainly consists two sub-strategies: A micro-grid autono-mous control strategy (ACS) base on state classification and a micro-source control strategy based on Carrier Sense Multiple Access with Collision Detection (CSMA/CD) mechanism. At different state levels, state classification control strategy adopts different control strategies for micro-sources by establishing system state classification model and evaluating system operation state. Thus, the operation state of each unit can be optimized from the system level; time-sharing control strategy which is based on CSMA/CD mechanism, quantifies the priority of participating level for each Controllable Micro-Generator (CMG). Thus, system can guarantee the control order for micro-sources and the uniqueness of main source. Hence, with the proposed ACS, one master distributed generator (MDG) can be decided when facing the state change of micro-grid. Then, some negative effects including current circulation caused by multi distributed generators (DGs) and distributed sources (DSs) adopting VF or droop control can be solved. So the stability of system can be improved. Simulation results based on PSCAD/EMTDC platform are presented to show the validity of the proposed ACS.