China Southern Power Grid Company

About: China Southern Power Grid Company is a company organization based out in Guangzhou, China. It is known for research contribution in the topics: Electric power system & Computer science. The organization has 2058 authors who have published 1478 publications receiving 8246 citations.

A Steady-State Analysis Method for a Modular Multilevel Converter

Abstract: Modular multilevel converters (MMC) are considered a top converter alternative for voltage-source converter (VSC) high-voltage, direct current (HVDC) applications. Main circuit design and converter performance evaluation are always important issues to consider before installing a VSC-HVDC system. Investigation into a steady-state analysis method for an MMC-based VSC-HVDC system is necessary. This paper finds a circular interaction among the electrical quantities in an MMC. Through this circular interaction, a key equation can be established to solve the unknown circulating current. A new steady-state model is developed to simply and accurately describe the explicit analytical expressions for various voltage and current quantities in an MMC. The accuracy of the expressions is improved by the consideration of the circulating current when deriving all the analytical expressions. The model's simplicity is demonstrated by having only one key equation to solve. Based on the analytical expressions for the arm voltages, the equivalent circuits for MMC are proposed to improve the current understanding of the operation of MMC. The feasibility and accuracy of the proposed method are verified by comparing its results with the simulation and experimental results.

A Heuristic Operation Strategy for Commercial Building Microgrids Containing EVs and PV System

Abstract: Commercial building microgrids will play an important role in the smart energy city. Stochastic and uncoordinated electric vehicle (EV) charging activities, which may cause performance degradations and overloads, have put great stress on the distribution system. In order to improve the self-consumption of PV energy and reduce the impact on the power grid, a heuristic operation strategy for commercial building microgrids is proposed. The strategy is composed of three parts: the model of EV feasible charging region, the mechanism of dynamical event triggering, and the algorithm of real-time power allocation for EVs. Furthermore, in order to lower the cost of computation resource, the strategy is designed to operate without forecasting on photovoltaic output or EV charging demand. A comprehensive result obtained from simulation tests has shown that the proposed strategy has both satisfactory results and high efficiency, which can be utilized in embedded systems for real-time allocation of EV charging rate.

Internet of Things Based Smart Grids Supported by Intelligent Edge Computing

Abstract: In this paper, an edge computing system for IoT-based (Internet of Things) smart grids is proposed to overcome the drawbacks in the current cloud computing paradigm in power systems, where many problems have yet to be addressed such as fully realizing the requirements of high bandwidth with low latency. The new system mainly introduces edge computing in the traditional cloud-based power system and establishes a new hardware and software architecture. Therefore, a considerable amount of data generated in the electrical grid will be analyzed, processed, and stored at the edge of the network. Aided with edge computing paradigm, the IoT-based smart grids will realize the connection and management of substantial terminals, provide the real-time analysis and processing of massive data, and foster the digitalization of smart grids. In addition, we propose a privacy protection strategy via edge computing, data prediction strategy, and preprocessing strategy of hierarchical decision-making based on task grading (HDTG) for the IoT-based smart girds. The effectiveness of our proposed approaches has been demonstrated via the numerical simulations.

Architecture of Nan'ao multi-terminal VSC-HVDC system and its multi-functional control

Abstract: This paper presents a framework of a multi-terminal HVDC transmission system and its multi-functional control strategy. The framework possesses the basic characteristics of the DC-grid and is suitable in integrating distributed power sources. The paper proposes the first architecture for a multiterminal HVDC transmission system using the VSC technology. Its control strategy offers various functionalities that include controls for operation mode, start-up and shutdown, DC voltage, and station online re-connecting, which are significantly different from the control of point-to-point VSC-HVDC systems. The framework has not only been evaluated in real-time simulation studies, but has also been implemented onsite for the first time via the China Southern Grid's Nan'ao Multi-terminal VSC-HVDC (VSC-MTDC) project. This paper gives a brief review of the current research and engineering achievements in this field, which includes four aspects: the architecture of the VSC-MTDC system, the structure of the control and protection system, simulation verification tests setting, and the results of real-time hardware in hardware in loop (HIL) simulation studies and onsite tests.

Resilience Enhancement With Sequentially Proactive Operation Strategies

Abstract: Extreme weather events, many of which are climate change related, are occurring with increasing frequency and intensity and causing catastrophic outages, reminding the need to enhance the resilience of power systems This paper proposes a proactive operation strategy to enhance system resilience during an unfolding extreme event The uncertain sequential transition of system states driven by the evolution of extreme events is modeled as a Markov process At each decision epoch, the system topology is used to construct a Markov state Transition probabilities are evaluated according to failure rates caused by extreme events For each state, a recursive value function, including a current cost and a future cost, is established with operation constraints and intertemporal constraints An optimal strategy is established by optimizing the recursive model, which is transformed into a mixed integer linear programming by using the linear scalarization method, with the probability of each state as the weight of each objective The IEEE 30-bus system, the IEEE 118-bus system, and a realistic provincial power grid are used to validate the proposed method The results demonstrate that the proposed proactive operation strategies can reduce the loss of load due to the development of extreme events