The power system consists of power generation, transmission, transformation, distribution and electricity consumption. Generally, generators, transformers, switches, transmission lines and other equipment are called primary equipment of power system. In order to ensure the safe, stable and reliable operation of primary equipment and the economic operation of power production, it is necessary to carry out on-line measurement and control, protection and dispatching control of primary equipment. In the power system, these measurement and control devices, protection devices, related communication equipment, computer systems of power grid dispatching control centers at all levels, (thermal) power plants, (hydro-nuclear energy,).
1. 1 power grid dispatching automation
1.2 substation automation
1.3 distributed measurement and control system of power plant
2. At present, power system automation depends on IT technology, an important hot technology.
At present, power system automation depends on electronic technology, and computer technology is developing continuously. The main hot spots are:
2. 1 intelligent primary power supply equipment
The installation sites of conventional power primary equipment and secondary equipment are generally tens to hundreds of meters apart, and they are connected with each other by strong signal power cables and large current control cables. Intelligent power primary equipment means that when designing the structure of primary equipment, some or all functions of conventional secondary equipment are realized on site, which saves a lot of power signal cables and control cables. Generally speaking, the primary equipment has its own measurement and protection functions. Such as common "intelligent switch", "intelligent switch cabinet" and "intelligent box substation". The main problem of intelligent primary power equipment is that electronic components are often interfered by high-intensity electromagnetic fields generated by large current interruption in the field. The key technologies are electromagnetic compatibility, power supply of electronic components and protocol standards of external communication interfaces.
2.2 On-line condition detection of power primary equipment
Long-term continuous on-line monitoring of important operating parameters of primary equipment such as generators, steam turbines, transformers, circuit breakers and switches in power system. It can not only monitor the real-time running state of equipment, but also analyze the changing trend of various important parameters and judge whether there are signs of failure, thus prolonging the maintenance cycle of equipment, improving the utilization rate of equipment and providing guarantee for the transition from regular maintenance to condition maintenance of power equipment.
Barriers. In recent years, the electric power department has invested a lot of money to cooperate with universities and scientific research units or introduce technology to carry out the research and practice of online condition detection technology, and has made some progress. However, due to technical difficulties, strong professionalism and harsh testing environment, it will take some time to develop satisfactory products.
2.3 photoelectric power supply transformer
Power transformer is an indispensable and important equipment in transmission lines, and its function is to reduce the high voltage and high current values on transmission lines to the standard values that can be directly measured by instruments, so as to be directly measured by instruments. Its disadvantage is that with the increase of voltage level, the greater the insulation difficulty, the greater the volume and quality of the equipment; The signal dynamic range is small, which leads to saturation phenomenon or signal distortion of current transformer; The output signal of mutual inductor can't directly interface with microcomputer measurement protection equipment. Therefore, many developed countries have successfully developed new photoelectric and electronic transformers, and the International Electrotechnical Association has promulgated the standards for electronic voltage and current transformers. There are also universities and scientific research units in China that are stepping up research and development and have achieved gratifying results. At present, the main problem is that the stability of materials is not ideal due to the influence of temperature coefficient. Another key technology is that the output signal of photoelectric transformer is much smaller than that of electromagnetic transformer, which is generally milliampere level. It can't be sent to measurement and control and protection devices through long cables like electromagnetic transformers, but it needs to be converted into digital signals on site and sent through optical fiber interfaces. Electronic circuits such as analog-to-digital conversion and photoelectric conversion need to be structurally integrated with transformers. Here, electromagnetic compatibility,
Insulation, environmental resistance and power supply of electronic circuits are also one of the technical difficulties.
2.4 New relay protection and measurement and control device adapted to photoelectric transformer technology
After the photoelectric transformer technology is adopted in power system, the structure and internal functions of related secondary equipment such as measurement and control equipment and relay protection will change greatly. Firstly, the isolation transformer, *+conversion circuit and some signal processing circuits inside the device are omitted, which improves the response speed of the device. However, the important key technology to be solved is to meet the needs of numerical calculation by analyzing the relevant data from different transformers, such as
How to realize synchronous sampling, and then design an efficient and fast data exchange communication protocol.
2.5 Development of secondary equipment in power grid
In the later period of the Tenth Five-Year Plan, in view of the demand of economic and social development for electricity, the pace of scientific and technological progress of power grid enterprises has obviously accelerated. In the field of UHV, which represents the highest level of power transmission and transformation technology in the world today, the feasibility study of UHV test and demonstration projects in southeastern Shanxi, Nanyang and Jingmen of State Grid Corporation of China has passed the review in late 1 month, and construction is expected to start at the end of the year. The UHV transmission voltage of this experimental demonstration project is 1000KV.
In addition, China Southern Power Grid Corporation is also preparing to build an 800 kV Yunguang UHV DC transmission line.
The primary and secondary equipment of UHV transmission lines need to be redeveloped or imported from abroad. The key technology of developing secondary equipment for UHV transmission is the stability control technology of UHV power grid and the solution of special problems such as electromagnetic compatibility, anti-interference ability and insulation of field equipment.