Introduction

Abstract

AbstractWith the rapid development of smart grid construction, the marketization of the world power industry is developing. In order to promote the economic development, the grid interconnection and the market construction are the main objectives of the power industry. As a part of ancillary service, frequency regulation plays an important role in the electricity market and has an important impact on the stability of smart grid. With the concept of demand-side management put forward, controlling the working state of load has become an effective method to regulate the power grid frequency. With the continuous improvement of people’s living standard, TCL accounts for a large porportion of industrial, commercial and residential electricity. The proportion of power consumption is rising, and the impact on the smart grid is gradually increasing, especially in the peak period of power consumption. If the TCL is not controlled, it is easy to cause serious problems such as power failure, power grid fluctuation and line burning, which will have an adverse impact on the power generation side, transmission network and users. In addition, with the introduction of renewable energy generation, demand side energy management is particularly important. TCL has high flexibility, which can be used as an energy storage system to control it properly and provide a variety of auxiliary services for smart grid. Based on the stochastic battery dissipation theory, the convergent TCL is equivalent to a generalized energy storage battery, and the adjustable energy threshold of frequency regulation service provided by large-scale TCLs is analyzed. The results show that the aggregated TCLs have the characteristics similar to energy storage device, and its adjustable energy storage capacity is limited, especially when the set value is unchanged. However, when the set value is dynamically adjusted, its energy storage capacity can be increased accordingly, so as to provide more services. However, under the control of existing controllers such as linear quadratic controller and internal model controller, the accurate control of convergent air conditioning load cannot be realized. Therefore, in the process of providing frequency regulation services for smart grid, the research focus is to ensure the energy storage capacity and control accuracy of aggregated TCLs.