State Grid Corporation of China, Nanjing Southeast University, BEI JING XJ Electrical CO. and Xu Ji Group Corporation | Date: 2013-04-18
The present invention provides an integrated battery dispatching system with centralized charging and centralized allocation, which comprises an initial parameter setting module (101), a dispatching selection module (102), a delivery parameter setting module (103), a full battery number acquiring module (104), a logistics fleet delivery strategy submodule (105) and a centralized charging station charging strategy submodule (106). The present invention integrally dispatches centralized battery charging, battery dispatching and logistics vehicle allocation, and arranges the battery to be charged with cheap electric energy according to the battery replacement demand of a delivery station in combination with the capacity constraint for a centralized charging station and the power tariff of a power grid. The four integrated dispatching subsystems involved in the present invention can meet the needs of different users, and the users can select a suitable operation mode according to their own characteristics and practical situations.
Chen X.,Tsinghua University |
Bo Z.,Xuji Group Corporation |
Dong X.,Tsinghua University |
Shi S.,Tsinghua University
Proceedings of the 5th IEEE International Conference on Electric Utility Deregulation, Restructuring and Power Technologies, DRPT 2015 | Year: 2015
The communication network of power system is often damaged after a disaster. To solve this problem, this paper uses ant colony algorithm to find the optimal circuitous route. Simulation results show that the method is fast, which can accelerate the recovery of the communication network. Besides, this paper does some research on the dead end problem, and analyses relationship between degree of adjacency and ratio of coming to a dead end. The result shows that the efficiency of ant colony algorithm can be improved only if it tries to avoid coming to dead ends. © 2015 IEEE.
State Grid Corporation of China and Xu Ji Group Corporation | Date: 2012-08-28
The present invention relates to an IEEE1588 protocol negative testing method, comprises steps of: connecting a IEEE1588 tester and a slave clock DUT to establish a real-time closed-loop feedback mechanism; taking the IEEE1588 tester as a master clock, and establishing a stable time synchronization with the slave clock DUT; obtaining the timing offset or path delay of the slave clock DUT before disturbance; assembling an abnormal message in a frame and sending it to the slave clock DUT; calculating the timing offset or path delay increment after disturbance of the abnormal message; determining whether there is a sudden change in the timing offset or path delay of the slave clock DUT, wherein if there is no sudden change, the test passes; otherwise the test fails. This testing method uses the field of correction field (correction Field) in the IEEE1588 message to magnify the response of the slave clock DUT to the abnormal message stimulus, and realizes a real-time closed-loop detection to efficiently verify whether the message processing logic of the slave clock DUT follows the IEEE1588 protocol.
Kong F.,Xi'an Jiaotong University |
Zhang B.,Xi'an Jiaotong University |
Wang Y.,Xi'an Jiaotong University |
Zhen W.,Sichuan Electric Power Research Institute |
Zhang A.,Xuji Group Corporation
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2014
In order to improve the reliability and sensitivity of single-terminal transient-based protection, an ultra-high-speed directional element is proposed for the relay protection of HVDC transmission line, which effectively determines the fault direction according to the difference between the forward traveling wave energy and the backward traveling wave energy when different fault directions exist. A closed-loop test system consisting of RTDS and HVDC control & protection devices is built to test the performance of proposed directional element. Results show that, immune to the fault location and transition resistance and suitable for different voltage levels and different operating modes of HVDC projects, it determines the fault direction accurately and rapidly, which improves the performance of single-terminal transient-based protection effectively. Besides, it can be used to form a pilot directional protection.
Zhang B.,Xi'an Jiaotong University |
Kong F.,Xi'an Jiaotong University |
Zhang S.,Xi'an Jiaotong University |
Zhang A.,Xuji Group Corporation |
And 2 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013
To solve the problems existing in traditional main protection for transmission lines, such as insufficient sensitivity and poor reliability, the novel non-unit main protection device based on transient signals for high voltage direct current (HVDC) transmission lines was developed on the present HVDC control and protection platform hardware and software. The protection scheme for HVDC transmission lines is based on the attenuation characteristics of line boundary for high frequency voltage signals and is composed of starting unit, transient signal based directional unit, boundary unit, lightning disturbance identification unit and fault-pole identification unit. All commissioning tests for control and protection systems of HVDC transmission lines were performed on the transient signal based protection device, which used control and protection devices, and RTDS simulation models for actual HVDC secondary system commissioning. The results show that the protection device can accurately identify internal faults, external faults and lightning disturbance at high speed, and is suitable for different HVDC projects. The protection principle is reliable and the amount of calculation is small; besides, the threshold values of each unit do not need to be changed when applied to different HVDC projects and the protection is feasible. © 2013 Chinese Society for Electrical Engineering.
Yi Y.-P.,University of Shanghai for Science and Technology |
Wang W.,University of Shanghai for Science and Technology |
Zu L.-F.,XUJI Group Corporation CO.
Guangzi Xuebao/Acta Photonica Sinica | Year: 2015
To reduce the test error, the orthogonal double beam spectrophotometer was designed. The orthogonal double beam spectrophotometer uses one photoelectric conversion system which includes one photodiode, one filtration and amplification, one AD conversion and adds a producer of orthogonal signal which is a rotatable disk and non-opaque somewhere. In each cycle the reference signal and sample signal get through the producer of orthogonal signal and project to the photoelectric conversion system. In this way, the signals collected by the photoelectric conversion system in each cycle are composite and consist of the reference signal, sample signal and dark current signal, each of which will be separated by the master control system of FPGA as each code and restored for the following calculation and analysis. Since the error caused by the differences of photoelectric transducer and collecting time is avoided theoretically, the measurement accuracy of double beam spectrophotometer can be improved through taking one photoelectric conversion system and adding a producer of orthogonal signal. The experimental results show that the orthogonal double beam spectrophotometer has advantages in stability and accuracy. © 2015, Chinese Optical Society. All right reserved.
Ma C.,Shandong University |
Gao F.,Shandong University |
Li R.,Xuji Group Co. |
Li X.,Xuji Group Co.
Dianwang Jishu/Power System Technology | Year: 2016
With increasing construction and grid integration of renewable energy generation in large scale, accurate and rapid low voltage ride through (LVRT) regulation and islanding detection are two important functions of grid-integrated systems. Grid-integrated system should operate LVRT and islanding detection simultaneously based on LVRT operation time and islanding detection defined in grid code in actual operation. Once islanding condition is detected, shut down operation shall be implemented. Existing LVRT and islanding detection methods, however, cannot be combined simply in detection time and structure and cannot achieve LVRT and islanding detection simultaneously. This paper therefore proposes a reactive power perturbation method, consisting of dual second order generalized integrator phase locked loop (PLL), power perturbation module and islanding detection module. This method can meet requirement of LVRT and islanding detection in parallel by controlling output reactive power of grid-integrated renewable energy systems and utilizing output reactive power to implement power perturbation. Finally, validity and accuracy of the proposed method was verified with simulation results. © 2016, Power System Technology Press. All right reserved.
Fu M.-P.,Xuji Group Corporation |
Ma H.-W.,Xuji Group Corporation |
Mao J.-R.,Xuji Group Corporation
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2012
Photovoltaic power forecast is significant to reducing the impact of PV generation integration on the power grid. According to the characteristics of power generation of photovoltaic and the factors impacting PV power output, a method of selecting similar days is proposed. By calculating and analyzing similarity degree, the historical data similar to the features of forecasted day are selected and considered as the training samples together with weather data. The least square support vector machine(LS-SVM)is used to calculate PV power output. The method is validated by photovoltaic system data of a micro-grid demonstration project and the forecast error is calculated and analyzed. The results show the method has high accuracy, which provides reference to forecast generation power of PV system.
Zhang J.,Xuji Group Corporation |
Jiang Y.-J.,Xuji Group Corporation |
Guo D.-Q.,Xuji Group Corporation
Gaoya Dianqi/High Voltage Apparatus | Year: 2010
Aiming at the opening current character and opening velocity character of the single coil and single stable permanent magnetic actuator which is used in 12 kV vacuum circuit breaker, the double coils and single stable permanent magnetic actuator which has one closing coil and one opening coil is suggested in this paper. In order to decrease opening current and increase opening velocity, a short circuit ring is fixed in the permanent magnetic actuator. The analysis and optimal design on the permanent magnetic actuator are performed by using the finite element method. The design scheme and test results are presented which indicate that the technical parameters meet the design requirements and the feasibility of the approach is verified.
Zhang H.,Xian Xuji Power Electronics Technology Corporation |
Wu J.,Xian Xuji Power Electronics Technology Corporation |
Yang M.,Xian Xuji Power Electronics Technology Corporation |
Yao W.,Xuji Group Corporation
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2015
For restraining inner circulating current in modular multilevel converter (MMC), this paper presents a novel restraint strategy for bridge arm circulating current, including improved topology of MMC, circulating current restraint method, constant voltage control of voltage correcting module (VCM). Second, for engineering applications, this paper proposes a redundancy control method of VCM, and the parameters of VCM are designed, including modular voltage and support module capacitance value. Simulation results show the reasonableness of the design of the proposed VCM parameters and verify the redundancy control scheme can maintain VCM voltage stability as well as effectively restrain bridge arm circulating current of converter. The proposed scheme applies to all MMC system and has obvious advantages in case of high voltage and large capacity like IGBT connecting MMC in series. © 2015, Power System Protection and Control Press. All right reserved.