Commissioning Test on the 1000 kV UHV AC Demonstration Project and Operation Monitoring of the Main Equipments

摘要

The 1000 kV Jindongnan-Nanyang-Jingmen UHV AC demonstration project developed byState Grid Corporation of China is the first UHV project in the country. The successfulconstruction of this project is of great significance to the reliability of China’s electric powersupply, and to the research and application of UHV transmission technology around theworld. This paper has provided an overview of the commissioning test, including the researchand determination of commissioning plan, testing results, and the evaluation to operationstatus of main equipments.Commissioning test is the initial work before putting the project into the commercialoperation. To guarantee the success of the tests, State Grid has started the research andpreparation at the beginning of the construction. The final system test has been confirmedbased on a large amount of calculation and optimization, including 15 experiments of threedifferent types.Voltage-raising experiments have been conducted to test the insulation of UHV equipments,to verify the polarity of CVT and CT, and to check the accuracy of relay protections. Suchexperiments should be taken in small isolated systems due to the requirement for the safety ofequipments and systems. When taking experiments on the 1000 kV UHV AC transmissionsystem, it is necessary to avoid generators' self-excitation phenomenon, otherwise it woulddamage power equipments due to the higher over-voltage. Meanwhile, there are several 500kV substations from generating units to UHV substations. The safety of Central and NorthChina power grids must be maintained once the bus bar of any 500 kV station is isolated fromthe nominal system.The experiments on equipments switching have been conducted to test the capability of UHVcircuit breakers and switching of electrical equipments, to check protective actions, and tomeasure the switching over-voltage. There are four test items confirmed eventually with the switching UHV no-load transformer, the switching no-load transmission line and low-voltagecompensating equipments.The 1000 kV UHV AC TL is the connecting line between North and Central China powergrids, with a gross installed capacity of over 3 million kVA. The network experiments areconducted to obtain the system operating characteristics and control rules, and to verify thevalidity of control strategies and simulations.Since the project is put into operation, it has realized a dual function, full voltage, and largetransmission capacity. It has withstood severe weather conditions such as thunderstorm,heavy wind, high temperature, frigid, etc, and has successfully undertaken a series of testsincluding annual examinations, as well as heavy transmission load in both summer andwinter. The system of this project has been operated stably, and all the equipments have beenworking smoothly. The technical and economical efficiency and reliability of equipmentshave been further approved. With the aim to maintain a timely and accurately commandoperation condition of equipments, a condition monitoring system for UHV substations andmain equipments of transmission lines has been developed. And the configuration principle,the functional composition, and the equipment operation condition of this conditionmonitoring system are also introduced in this paper.The successful construction of UHV AC demonstration project in China symbolizes the majorbreakthrough in key technology and equipments of the UHV AC system, which is of greatsignificance to the reliability of China’s electric power supply, and the research andapplication of UHV transmission technology around the world.