| With the rapid development of smart grid in China, the application of new equipment and new technology is changing rapidly. Superconducting Current Limiter, Superconducting Cable as the benchmark of the new equipment in the national grid has been a demonstration application. In the steady state operation, the economic performance of the power system can be improved, and the short circuit capacity can be reduced and the security of power grid operation is improved in the fault. Distributed power supply is the important way of renewable energy, which is in the comprehensive construction stage, and promotes the development of low-carbon power system. Advanced measurement technology is the base technology of smart grid, of which optical fiber sensing technology has many advantages, such as strong ability of anti-electromagnetic interference, low loss, wide transmission frequency range and so on, which has good application effect in the field of power system information measurement. Communication technology is the basis of smart grid. Our country has completely independent intellectual property of Beidou Navigation Satellite and Communication System, and in rural power system information monitoring, power line patrol supervision system has a good application prospect.The application of new equipment and new technology in smart grid environment presents new challenges to the operation of power network. Relay protection of power system is an important guarantee for the safe operation of power system. As new equipment for smart grid applications, superconducting current limiter and superconducting cable bring the advantages to power grid operation, but they have an impact on the conventional relay protection of power system. For example, the special electrical characteristics of the superconducting cable may lead the protection to error action or not act incorrectly. Distributed energy inserted into distribution network is the main application form of green energy, which makes the distribution network become a source of power distribution network. Current protection and distance protection in original distribution network has been unable to meet the requirements of multi-source distribution network safe operation, which means that people need to look for new solutions. Optical fiber sensing technology needs to adapt to and meet the requirements of the power system equipment to protect the required information, such as anti-jamming ability, high accuracy and real-time requirements. Beidou satellite navigation technology information transmission is not strong enough while power system protection and monitoring requires a lot of information. How to combine them effectively is an important problem in the application of electric power system.The paper is based on the application of new equipment and new technology in the smart grid environment, and the key points of power system protection, and the following research work is carried out:1. For Superconducting Current Limiter, Superconducting Cable new equipment, the effect of the new equipment on the current protection of the power network is studied, and a feasible setting method is proposed. Firstly, the paper discusses the influence of the superconducting cable and the superconducting current limiter on the protection of the three phase current and the zero sequence current; Then the influence of the three phase current protection is analyzed after the combined input of the superconducting cable and the superconducting current limiter, and under normal circumstances it is conducted that time limited speed protection needs to be adjusted, the time limit for the current protection of the impact is very small, and the three phase current setting method is studied. Then the influence on zero sequence current protection is analyzed, and line zero sequence network structure is changed after the discovery of joint investment, and has reduced the scope of protection of zero sequence current protection ?, ? period, so need to set the value of its action setting, and the method of zero sequence current protection is studied.2. The effect of the superconducting current limiter and the superconducting cable joint investment is studied, and the feasible setting method is proposed. Firstly the three section distance protection is found to have a large capacity of the superconducting cable, and the superconducting current limiter is larger, so the impedance characteristic of the conventional line is different from that of the conventional line, which can result in reduction of the distance I, II protection to cause the protection to refuse to move, and the method of distance setting for the three stage is studied. Then the power frequency variation distance protection is found after the equipment is put into operation, when the line has a forward fault, it will cause the protection scope to be smaller and the protection will not be changed, when the reverse fault occurs, the capacitive reactance of the superconducting cable is much larger than the inductive impedance leading to current reversal, and will be caused by the protection of false. At last, the solution scheme is put forward from two angles, the length of the superconducting cable and the setting value.3. The influence of distributed power supply on the protection of current is studied in the distributed power supply network. With the application of the superconducting current limiter, the application of superconducting current limiter is studied to reduce the adverse effect of the distributed power supply, and a coordinated solution for the superconducting current limiter and current setting is proposed, and the maximum allowable access capacity of the distributed energy is determined. Firstly, the paper is aimed at the protection of the reverse time limit, and the superconducting current limiter is applied to the distribution network. On the basis of analyzing the mechanism of distributed power access to the protection of the anti-time limit, the coordination problem of the distribution network anti time protection is solved by the minimal parameter configuration of the proposed superconducting fault current limiter. And then for the three section current protection, a method for selecting the impedance of a superconducting fault current limiter and its protection setting value is proposed. Under the premise of considering the changing operating mode of the system and the distributed power supply, it guarantees the selectivity of protection well. In view of the analysis and research of the access capacity of the distributed power supply, the application of superconducting current limiter can effectively improve the access capacity of DG, and the access position of the distributed power supply has a great influence on the access capacity of the access to the superconducting current limiter.4. For new technology for optical fiber sensing, a method for monitoring transformer winding deformation based on distributed optical fiber sensing technology is proposed. Firstly, according to the electromagnetic wave theory of light, the working principle of optical fiber bending sensor is analyzed in theory. The feasibility of OTDR sensing system is confirmed by the experimental results. The accuracy of the transformer winding deformation and position deformation is analyzed by analyzing the magnitude and time of the optical power signal received by the optical receiver. Through the experimental system, it is found that the method can be used to monitor the mechanical deformation of the transformer windings and position of deformation in real time, and has the advantages of high sensitivity, high resistance to electromagnetic interference and good insulation, so that the reliability of transformer protection is improved.5. For Beidou satellite navigation and communication technology, the paper analyzes the Beidou communication system application in power system of conventional channel failure as the feasibility of the communication system of the third line of defense, and solve the fault in the process of compass information channel in power system protection information selection and queueing problems and improve the safety of power system protection information transmission channel. Firstly the Beidou satellite navigation communication system were introduced in detail, and compared the Beidou communication and optical fiber communication and other communication channels, analysis the application of Beidou communication system as the feasibility of the communication system of the third line of defence in the conventional channel power system failure. Then, it analyzes the problems in the application process, such as the amount of data required to be overcome, the large communication time interval, and no reliable data transmission mechanism. Subsequently, the fault in the process of compass information channel is limited and fault information need concentrated the queuing delay problem, build the priority queue algorithm to solve the problems in parallel data received. At last, the problem of the fault information is transported in the same time, the protection of the importance index and priority is defined, and the receiving of the data with high real-time requirements, such as the protection of power system, is ensured. |
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