Research On Voltage Response Strategy In Distribution Network Based On Grid Friendly Loads

Intelligent electricity has been one hot spot but a difficult point of the research ofsmart grid. To make the way of power supply and utilization more flexible andinteractive is the development tendency of intelligent electricity, whose keycharacteristic is interactivity of energy, information and operation between power gridand customers.This paper is aimed at researching a voltage control strategy which makes userdevices respond to the operation states of power grid automatically. It helps to achievethe flexible interaction and sufficient coordination between the user devices and powergrid, contributes to maintain the grid voltage at a steady point, helps to maintain thepower grid operate safely and stably, benefits to lead the rational utilization of power,aims at energy conservation and emission reduction. To achieve this goal, the papercarries out several specific tasks below. First, it presents the characteristics and typesof Grid Friendly Load (LGF), analyzes the development potential for Grid FriendlyLoad, and researches in the advantages of air conditioner load as grid friendly loads.Second, the reactive power characteristics of air conditioner load have asignificant impact on the voltage of distribution network. As a result a precise modelfor air conditioner loads is the foundation for accurate power system analysis. Due tothe diversity of air conditioners, this paper presents a new method for aggregation ofair conditioners, taking into account load clustering based on self-organizing featuremap (SOM). The simulation results show that, compared to the aggregation withoutclassification, the method proposed in this paper can improve the simulation precisionof air conditioners in distribution network obviously, and simulate the dynamiccharacteristics of a group of air conditioners better. Based on the aggregation model, itanalyzes the characteristics of a group of air conditioners, including the voltagecharacteristics, starting characteristic and the influence on the voltage of distributionnetwork.Third, this paper focuses on the voltage control strategy of grid friendly load. Inthis part, it comes up with two different control strategis, where customer devices areexpected to make a dynamic response to the distribution voltage and change theoperating conditions according to the real-time status of the distribution voltage. Byusing PSASP/UPI, it shows that the voltage control strategis can not only improve thevoltage drop amplitude, but also cut down the recover time of the grid failure. Last, this paper proposes a novel method to estimate the economical efficiency ofthe voltage control strategy in terms of voltage drop. In this work, it presents thevoltage sag probability model based on Monte Carlo method; it also presents thevoltage sag expense and the annual total expense model based on the intervalcharacteristic of customer satisfaction principle. The case proves that the voltagecontrol strategy can reduce voltage sag loss cost of power network, thus it proves theeffectiveness of the method in this paper.This paper proposes a voltage control strategy which can change the operatingconditions of terminal equipments by the real-time running status of power grid,without influencing the electricity consuming experience, assisting to maintain thepower system safe and stable, which can reflect the essence of intelligent electricity.