Advanced Materials Research Vols. 960-961

Abstract: In order to face the challenge of our economy and the environment, it is needed to speed up the energy structure transition and UItra High voltage (UHV) transmission has become an inevitable choice. Researches on the influence of UHV project to Jiangxi power grid are carried out in this paper. Using advanced digital power system simulator (ADPSS), the real-time simulation model of Jiangxi power grid is build up including the UHV project. Based on the simulation model, the problem of low frequency oscillation in Jiangxi power system is studied after the UHV power transmission project accessed. The influence of the UHV transmission line faults on system stability of Jiangxi grid is also researched.

Abstract: One of the most important ways to enhance the speed of state estimation is to establish the constant matrix Jacobian. This essay puts forward a new type of orthogonal transformation state estimation method based on Generalized Tellegen's theorem. This paper uses orthogonal transformation method to improve state estimation’s numerical stability, and makes the algorithm enjoy an ideal convergence. Moreover, it has strong compatibility of various distribution measurements. The method put forward in this essay has been verified through IEEE-30 Node System, and the efficiency of it has been fully proved by the example results.

Abstract: Take full advantage of the PMU's accurate mass measurement data is the effective method to improve the calculation accuracy of power system state estimation. This essay puts forward the state estimation method of power system based on the Taylor series method. It analysis of power system operating conditions based on the real-time measurement of Wide area measurement system, divides the state time, establishes the equation of state of the measurement data by curve fitting method in the period of state time, creates a new state estimation calculation method by Taylor series method, constructs a new voltage characteristic curve calculation method, determines the system state and achieve the continuity of power systems steady-state analysis. The method put forward in this essay has been verified through IEEE-30 Node System, and the efficiency of it has been fully proved by the example results.

Abstract: Abstract: The evaluation of small current grounding line selection device plays an important guiding part in fault diagnosis and device promotion. But the current methods focus on the evaluation of individual indicator and can not form systematic evaluation of the programs.This paper firstly makes use of AHP method to evaluate small current grounding line selection device, and establishes the evaluation system of small current grounding line selection device. During the weight solution process, this paper uses three scale method to determine the comprehensive weight of individual indicator, and achieves a combination of expertise and quantitative, qualitative assessment of the results. The practical case analysis of small current grounding line selection device proves the validity and practicability of this method, which is of great theoretical and practical significance.

Abstract: This paper introduces renewable energy to ensure offshore platforms as a stand-alone microgrid operate reliably economically in low-carbon environment, considering volatility of CO₂ emission price. A probability distribution model and economic model containing investment cost and low-carbon effect is established respectively, using latin hypercube sampling (LHS), meanwhile, the stochastic power is adopted to judge whether the built planning model can meet power flow constraint, Monte Carlo method is used to simulate characteristics of distributed generation ( DG), a probabilistic power flow is made to illustrate reliability index. The model takes the types, sites and sizes of DG as decision variables, economy and environment as the objective function, particle swarm algorithm is proposed to solve the multi-objective optimization problem .A case study based on data from offshore oilfield is presented to verify the advantages of the improved optimal sizing method.

Abstract: Based on frequency synchronization theory of the second-order non-uniform Kuramoto model, a novel approach for power system transient stability analysis is put forward by establishing the correspondence between the classic power system model and the second-order non-uniform Kuramoto model. This method relates network parameters with the region of attraction of the disturbed system’s stable equilibrium and thus the transient stability information of the disturbed system can be obtained by comparing the initial configuration with trapping region of the stable equilibrium of the disturbance-canceling system. The application of our approach to single machine infinite bus system shows that this method features a fast computation speed. It can determine the transient stability of the system when a certain perturbation acts on as well as offer the stability margin of the disturbed system, which is of great importance for practical use.

Abstract: The article studies on the application of the shuffled frog leaping algorithm (SFLA) in power distribution network reconfiguration, taking the minimum loss and voltage quality of distribution network as a multi-objective function. The article improves the initial solution generation strategy of traditional genetic algorithm, which ensures the initial solution is feasible solution. Shuffled frog leaping algorithm and genetic algorithms are combined and proposed as shuffled frog leaping genetic algorithm (SFLGA). The algorithm uses the efficient coding strategy based on the basic loop and initial solution generation strategy, improves the calculation efficiency. The algorithm is verified by simulation results from test case on IEEE 33-bus system with distributed generations.

Abstract: SSDC(Supplementary sub-synchronous oscillation damping controller) is one of effective measures to suppress the SSO(sub-synchronous oscillations) caused by HVDC. The article researched the phase compensation method of SSDC on the basis of studying the SSO and the SSDC mechanism in depth. We verified the validity of the method used by designing SSDC in an large domestic HVDC simulation model. And we find that the SSDC designed can effectively increase the positive electrical damping in the sub-synchronous frequency range with the sub-synchronous frequency scanning to suppress the SSO.

Abstract: With the improvement of living standards, people want to have a comfortable, convenient, safe working and living environment. In this context, the traditional architectural forms has been unable to meet the basic needs of the people. Therefore, in recent years, the intelligent building has been rapid development in our country.In the intelligent building, electrical equipment occupies a very important position. For reliability and safety considerations, the power requirements of various equipment in intelligent building is very high.This paper designs a kind of intelligent building power monitoring system based on Internet of things. This system treating embedded hardware as the core, basing on ZigBee wireless communication technology for signal transmission, using GPRS communication technology to remote monitoring system, achieved the control of a variety of equipment in the power system in the intelligent building of local . The test result shows that this system runs stably, and has practical application value.

Abstract: The index system for electrical characteristics of metal-oxide surge arresters is proposed and established, which is based on rated voltage (U_r), continuous operating voltage (U_c), nominal discharge current (I_n), overvoltage protection and insulation coordination including lightning overvoltage protection level, operating overvoltage protection level and coordination coefficient (K_s). The study considers both selection and application of overvoltage protection devices for the electrical equipments in 3-35kV medium voltage power system, and comparatively calculates and analyzes the main parameters between two types metal-oxide surge arresters (without gaps and containing series gapped structures), and illustrates their technical features and puts forward suggestions on how to improve the effective utilization. The results of 10kV power distribution system are simulated to show that the conclusions are feasible and available in the practical engineering application.