Electric energy quality monitoring system for electric vehicle charging station

Abstract

The invention relates to the technical field of the electric energy quality of electric power systems, in particular to an electric energy quality monitoring system for an electric vehicle charging station. The electric energy quality monitoring system is suitable for electric energy quality monitoring, evaluation and treatment of the electric vehicle centralized charging station and is constituted by mutual connecting of three parts of an electricity supply system, a charging system and a monitoring system. The electricity supply system, the charging system and the monitoring system are connected with a charging station electric energy quality monitoring device; a direct current charger electric energy quality monitoring terminal and an alternating current charger electric energy quality monitoring terminal are connected between the charging system and the charging station electric energy quality monitoring device; and the monitoring system is further connected with a center server, a management client and a data server. The unified time service function is achieved, safety can be guaranteed to the largest extent, electric energy quality monitoring, analysis, evaluation and forecast of the charging station are achieved, the electric energy quality problems caused by a single charger branch and a charger are located, analyzed, compared, evaluated and diagnosed, and consistency and comparability of all measurement points data are guaranteed.

Description

technical field [0001] The invention relates to the technical field of power system power quality, in particular to a power quality monitoring system for electric vehicle charging stations, which is suitable for power quality monitoring, evaluation and management of electric vehicle centralized charging stations. Background technique [0002] Electric vehicles are one of the key directions for the development of new energy vehicles, which are of great significance to energy conservation, environmental protection, and carbon emission reduction. Electric vehicle charging facilities are an important part of the electric vehicle industry chain, so the development of charging facilities and the charging facilities are fully considered. The impact on the power quality of the grid is very important. [0003] At present, a variety of electric vehicle charging modes have been proposed at home and abroad, mainly the most common slow charging mode, that is, charging electric vehicles w...

AI Technical Summary

Problems solved by technology

In particular, centralized electric vehicle charging stations, which are put into use in large quantities, will not only have an impact on grid planning and capacity expansion, but also have a great impact on the power quality of the power system, mainly manifested in: load imbalance, that is, When the charging station adopts high-current fast charging, a large current of 150-600A will be formed, which may cause grid instability, and excessively intensive centralized charging may cause the instantaneous load of the charging station to be too large, which will affect the load regulation and load capacity of the grid. As well as the power supply capacity are all tested; harmonic pollution, that is, the use of large-capacity chargers of power electronic devices to generate harmonics, causing additional loss and heat generation of lines or transformers, causing local inductance and capacitance in the power grid to resonate, making harmonics further Amplified, higher harmonics can lead to misoperation of control equipment, resulting in interruption of production or operation; for switches and relay protection equipment, harmonics may cause abnormal tripping of solid-state tripping devices of electronically protected low-voltage circuit breakers, It may interfere with the protection and automatic devices of the starting elements composed of sequence component filters; as well as voltage deviation, frequency deviation, voltage flicker, three unbalanced, etc.

[0004] At present, there is no power quality monitoring system for electric vehicle charging stations, especially centralized electric vehicle charging stations that use a large number of large-capacity DC fast chargers. In particular, the current charging stations may be equipped with power quality monitoring systems, or power Quality control methods, for example, for the electric vehicle charging stations that have been put into operation, adopt the method of harmonic control on the grid side, invest in specific equipment for harmonic control to prevent the charging station from injecting harmonic current into the grid, all of which are aimed at the entire charging station Monitoring and protection of power quality, but not online monitoring, evaluation, and management of a single substation branch, such as a DC charger

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