Advanced Materials Research Vols. 860-863

Abstract: With the popularization of the rural electricity utilization, the rural electric safety was still an immediate problem to be solved. It was difficult to exactly detect and judge electric shock signals in the summation leakage current on the low-voltage electric power grid. A detection method of electrical contact signals based on sliding window and wavelet multi-resolution method was proposed. Under the different signal-to-noise ratio level, the summation leakage current was reconstructed by wavelet decomposition reconstruction algorithm. According to the characteristic of the slow change of the normal leakage current and the rapid change of the electric shock current within a short time, the electric shock current were extracted from the restructured summation leakage current signal by sliding window method. The mean square error and correlation analysis between the extracted signal and the actual testing results were studied. The analysis results show that the proposed method could identify electric shock current in the summation leakage current among noise, and its detection precision was superior to single sliding window method.

Abstract: This paper presents a novel modified bacterial foraging optimization(BFO) to solve economic loaddispatch (ELD) problems. BFO isalready successfully employed to solve variousoptimization problems. However original BFOfor small problems with moderate dimensionand searching space is satisfactory. As searchspace and complexity growexponentially in scalable ELD problems, it shows poorconvergence properties. To tackle this complex problem considering itshigh-dimensioned search space, the Evolution Strategies is introduced to thebasic BFO. The chemotactic step is adjusted to have a dynamic non-linearbehavior in order to improve balancing the global and local search. Theproposed algorithm is validated using several thermal generation test systems.The results are compared with those obtained by other algorithms previouslyapplied to solve the problem considering valve-point effects and power losses.

Abstract: Fault diagnosis is an effective means to assure the safe operation of power system. In this paper, a detection and monitoring of transformer fault diagnosis of multi-source data fusion technology is introduced. Based on the correlation distance, to calculate the relationship between detection and monitoring data and equipment failure, using the weight function to set fault indicators, status online monitoring data over the fault indicators, judging the equipment what kind of failure is happened, improving the precision of fault diagnosis.

Abstract: APF harmonic detection is the study of the most important parts of the core , quickly and accurately detect the harmonic current is able to quickly output harmonic compensation circuit current of the premise. Delay compensation system is based on the increase in the method specified time compensation angle , which can accurately detect the harmonic current at the same time , the low-pass filter to minimize the time delay generated by MATLAB simulation, the use of delay compensation system active Filter harmonic Detection and Compensation excellent performance, while ensuring high precision detection and compensation while ensuring at the same time , and fully complete filter real-time functionality .

Abstract: To analysis the main factors that lead to device fail and identify the fault indicator , this paper proposes a method about correlation identification between the multi-factor and equipments failure. Firstly, this paper sets the related factors influencing the equipments failure as numerical value, based on distance correlation definition, calculate the correlation between each factors and equipments failure. So that determines the power of the main causes of equipments failure. At last, through 330 kV transformer fault case validates the effectiveness and unbiasedness of the proposed method.

Abstract: After analyzing briefly the structure of hydropower substation monitoring system, positioning system roadway based on RFID was put forward connected with communication and monitoring networks existed already. the separate monitoring systems of environment is integrated with the former comprehensive automation system into a unique system. It's a new step of substation automation. The system architecture, software, hardware and the necessary factions of this system are introduced in detail for reference of practical design. In Hydropower substation tunnel, monitoring identity code terminal station are set along the power line information, collect personnel information data by receiving wireless signals.

Abstract: The study on the HVDC based on voltage-source converter focuses mainly on the control strategy while less on the impact of electrical damping on the adjacent units by VSC-HVDC. The mechanism of VSC-HVDC on inhibiting sub-synchronous oscillation is analyzed theoretically in the respect of its operation principle. Then the complex torque coefficient method realized by time domain simulation-the test signal method, is adopted to investigate the impact of the unit interaction factor, control mode, active power level and reactive power level on the electrical damping on the adjacent units.

Abstract: Safety and stability control device is the secondary line of defense of power system stable operation. Firstly, this paper proposed the requisite of the regional safety and stability control system installed in Wuzhou 500kV switching station and the other two stations which belonged to the middle Henan power system. And then, it presented the components and elaborated control strategies of the system. It listed the situations of the united testing, at last, it summarized notes of this safety and stability control system in daily operation.

Abstract: The electric company of a distribution system purchases different kinds of electric energy including wind power energy to serve the load. Therandomness of wind power adds to the uncertainty of system reliability.Meanwhile electric energy storage at distribution level has the benefit of electric energy time shift and power supply capacity. Combining the two of them, an adequacy decision model is proposed to solve enerating capacity purchase scheme and charging and discharging schedule of the electric energy storage as well. The results of simulation show that the proposed method works well.

Abstract: Backup protection chain tripping caused by flow transferring is one of the most concerned issues in power system. The introduction of wide area backup protection is an effective way to solve the problem. However, in wide area protection system, an effective fault location puts forward a high demand for the location algorithm. This paper presented a method which combined effective mathematical methods with fault location calculation in power system together: firstly used fuzzy clustering analysis method for fast classification of voltage, locked the fault area, and prevented the occurrence of even jump accident at the first time. Then determined the fault location by calculating additional nodal current ratio in the fault area. The method avoids the repeated modification of network structure after fault. It lock the fault to the component quickly and improves the efficiency of fault location greatly.