In recent years, China has proposed a power grid development model for building a strong smart grid. The construction of intelligent substation is an important part of smart grid. The intelligence of substation is the basis of intelligent grid. The realization of substation intelligence is mainly composed of two parts, one is to build an intelligent substation, and the other is to transform the already operated conventional substation into a smart substation through the intelligent transformation of the substation.
With the rapid development of China's economy, changes in the global economic situation and energy development pattern have made clean energy, sustainable development, energy conservation and environmental protection, and low-carbon economy become the focus of the world. As the main carrier of resource optimization and configuration, the power grid is essential for promoting energy development, improving energy efficiency, and optimizing energy consumption structure. Relying on modern information, communication, sensing and control technologies, improving the level of intelligent power grids, transforming the mode of power development, and giving full play to the role of optimal allocation of power grid resources has become the only way for the development of China's energy and power industries. In conventional substations, there is no interoperability between devices, information is difficult to share, system reliability is affected by electromagnetic interference, etc., so that the operation of existing substation can not meet the requirements of social production and life. On the other hand, smart grid Reliable, stable, safe and economical operational targets also place higher demands on existing substations.
At present, the automation level of 110kV substation in most places in China is not high, the equipment in the station is outdated, and the station capacity is poor. In the southern snowstorm in 2008, we investigated the operation of substation equipment in Hunan, Guangxi, and Yunnan provinces. In many 110kV substations in the central and western regions of China, there are still fewer oil circuit breakers and some manual knife gates. Through the intelligent transformation of substation, the number of operations of substation equipment can be reduced and the workload of maintenance can be reduced, the reliability of equipment operation can be improved, and the operational management level can be improved.
Goals and advantages
According to the strategic goal of the State Grid Corporation to build a unified and strong smart grid, the conventional substation has been intelligently transformed into a smart substation with high degree of automation such as digital, network, standardization and interaction. Due to the large number of conventional substations currently available, an important part of the construction of intelligent substations is the intelligent transformation of conventional substations into intelligent substations. Therefore, the intelligent transformation of conventional substation occupies an important content position in the construction of smart grid.
In the intelligent substation of building a strong smart grid, the State Grid Corporation proposed the goal of building a smart substation. It is generally believed that the intelligent substation is based on digital substation and adopts advanced sensors, electronics, information, communication, control, intelligent analysis software and other technologies to establish a digital unified application platform for all information collection, transmission, analysis and processing of the whole station. Realize the automatic control operation of the substation, equipment state maintenance, operational state adaptation, improve management and operation and maintenance level. In the intelligent substation, the optical fiber replaces the cable between the secondary device and the primary device, replaces the traditional transformer with the electronic transformer, changes the traditional primary device into the intelligent primary device, and adds the merging unit and the intelligent interface. Compared with the traditional substation, the structure is compact, the layout is more reasonable, and the floor space is small. The use of low-cost, low-quality optical fibers reduces the use of non-ferrous metals, contributing to environmental protection and energy conservation. In order to extend the service life of the equipment, improve safety and reliability, and maintain the level of operation and maintenance, the equipment is managed for life cycle. The intelligent substation absorbs the advantages of the digital substation. Based on the digital substation as the technical architecture, it realizes one-time equipment intelligence, secondary equipment network, information exchange standardization, operation control automation, equipment condition maintenance, economic operation and optimization control. And smart alarms and other functions.
(1) Intelligent primary equipment is an important part of future intelligent substations. The application of optoelectronic technology makes it possible to realize intelligent functions such as online monitoring, intelligent control, and digital interface.
(2) A reliable, real-time, and efficient network system is one of the keys to communication systems. The networking of secondary equipment solves the exchange of information between the substation automation system and other systems.
(3) The intelligent IEC has adopted the unified IEC 61850 protocol for information interaction from the process layer to the control center. The information modeling of various equipments in the substation is carried out under the framework of the IEC 61850 protocol to realize information exchange and sharing inside and outside the substation.
(4) It is equipped with sensors for monitoring the main equipment of the system, collecting various operating state characteristic quantities of the main equipment, providing data for state maintenance, thereby realizing state maintenance of the equipment.
(5) If the main equipment in the substation is abnormal and faulty, the system protects the main protection according to the parameters already set, records the time and situation of the period, provides a status analysis report, and gives the cause of the failure. Handle comments.
(6) Realize optimal control and economic operation, coordinate and optimize control of grid reactive devices from the perspective of the whole network, improve voltage qualification rate, improve power quality, achieve network loss reduction, achieve system safety and economic operation and optimize control .
Intelligent substation can complete information acquisition and information processing that is wider, deeper and more complex than conventional substation. The interaction between substation, station and dispatch, station and station, station with large users and distributed power is stronger. More convenient and efficient information fusion and exchange, more reliable and flexible control. It adapts to the requirements of industrialization, such as easy transformation, easy expansion, easy upgrade and convenient maintenance.