Research On Voltage Response Strategy For Microgrid Based On Resident Controllable Load

Microgrid is a small autonomous power distribution system, includingdistributed generation, energy storage devices and loads. Microgrid takes theadvantages of distributed generation while weakening the negative effects ofdistributed generation on the grid, Microgrid has the advantage of high power supplyreliability, flexibility, economy and environmentally friendly. However, themicrosources in microgr id are significantly influenced by natural conditions,resulting in their random, intermittent and uncontrollable output power. It easilycauses voltage fluctuations, especially for the microgr id that is operated in island.Therefore, microgrid usually consists of a certain capacity of energy storage unitand reactive compensation device to maintain the system voltage stability, whichresults in the increase of power grid construction cost.Residential controllable loads such as thermostatically controlled loads (TCL)are t hermal energy storage equipment, which can store energy for several minutes oreven hours and can substitute traditional energy storage system. In addition,compared to the resources in generation side, Residential loads are extremelydecentralized, which can provide reserve to make rapid response in just a fewminutes or less. Therefore, response made by residential controllable loads issignificant to improve the microgrid operating characteristics and its voltagestability control. Focusing on residential controllable loads responding to the voltageto improve the voltage stability in microgrid, this paper makes the maincontributions which are listed as following:First, this paper summarizes the concept, basic structure and control technologyof microgrid. Also, the current status of microgrid has been reviewed and theapplication status of residential controllable loads in the microgr id has beenconcluded.Second, the paper researches the feasibility of residential controllable loadsmaking response to the microgr id voltage is.Then, based on the above analysis,control strategy for residential controllable loads to respond to the microgridvoltage is proposed. Through t he control strategy,residential controllable loadsmakes response to the system requirement actively by changing the triggertemperature of the control system, providing ancillary services in maintaining themicrogrid voltage stability. Moreover, the residential controllable loads voltage response capacity in the strategy under different microgrid operat ing status isanalyzed in detail.Third, in order to improve the accuracy of the control strategy simulation, theaggregation model of residential controllable loads is made accurately. Theeffectiveness of the proposed method is verified in PSASP.Finally, different simulation scenarios have been considered to compare thevoltage stabilit y with/without the proposed response stra tegy, which includesrandom energy fluctuations and load fluctuations. The effectiveness of the proposedresponse strategy is verified by the simulation..