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Da’anshan, China

Sun H.,Tieling Normal College | Zhao C.,Rongxin Power Electronic Co.
Gaoya Dianqi/High Voltage Apparatus | Year: 2014

This paper analyzes the grid code requirements on wind power/photovoltaic grid connection in domestic and then introduces their characteristics of low voltage ride through (LVRT), grid adaptability and testing devices. According to the current standard system, a LVRT and a grid adaptability testing device are developed respectively. Working principle and features have been introduced in this paper, meanwhile, the devices have been applied in a photovoltaic power station and the features have been verified. The test results show that; the two devices are convenient, reliable, which are independently tested, and can fully meet all technical specifications and functional requirements relevant to wind power/photovoltaic grid connection. Source

Lei L.,Guangdong Power Grid Corporation | Li Y.,University Of Science And Technology Liaoning | Hu G.,University Of Science And Technology Liaoning | Zhang Y.,Guangdong Power Grid Corporation | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2013

In order to achieve the energy-saving operation of high-voltage high-capacity static synchronous compensator(STATCOM), we discussed the switch choice, controlling method, and controlling strategies of STATCOM based on the 35 kV/±200 MVA cascade STATCOM adopted in China Southern Power Grid. After comparing the opening and closing losses and the driving power of IGBT, IGCT and IEGT, it is suggested that IEGT is the best choice from the aspect of energy saving. Furthermore, we analyzed the disadvantages of PWM inverter, and proposed to adopt an assistant-resonant soft-switching topology in PWM controlling inverters of the target system, which could reduce the operating loss and deal with the conflicts among the carrier frequency, reactive power waveform and device losses of inverters. Considering the parallel operation of target STATCOM, an energy-saving optimizing mathematic model of multiple parallel connected STATCOM for establishing energy-saving operation strategy was established. Moreover, analyzing the transient reactive power requirements of Guangdong Power Grid, we proposed a cooperating controlling strategy for STATCOM and existing reactive power compensation devices: STATCOM act firstly, then turn into/out the capacitor or reactor when the compensation capacity was at the setting quota. Further simulative and experimental data indicate that, by using the proposed methods, about 30% of the STATCOM loss can be saved. Source

Gao M.,Guangdong Power Grid Corporation | He G.,University Of Science And Technology Liaoning | Hu G.,University Of Science And Technology Liaoning | Zhang Y.,Guangdong Power Grid Corporation | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2013

Taking the 35 kV/± 200 MVA STATCOM of China Southern Power Grid as an example, we researched the reliability of high voltage and high capacity STATCOM. The "pyramid" integrated assessment model was used to establish the reliability model of the STATCOM's core parts, i.e. the valve block unit and the main circuit structure, and forecast their reliabilities. Considering that the accuracy of reliability analysis is not high due to the shortage of data and structure, the Bayesian information fusion method was used to theoretically analyze the reliability of a k/n(G) system model in STATCOM's main circuit structure for the lack of system experimental and operational data. The estimation results are consistent with those from field operation, indicating that the accuracy of the reliability estimation is improved. It is proposed that the complete statistic and regular arrangement of field test information and operating data should be one of the major tasks for further reliability studies of STATCOM. Source

Lu J.,Jiangsu Electric Power Company | Xiao X.,North China Electrical Power University | Zhang J.,North China Electrical Power University | Lv Y.,Rongxin Power Electronic Co. | Yuan C.,North China Electrical Power University
Electric Power Components and Systems | Year: 2016

This article presents a novel coordinated control approach for a unified power quality conditioner based on a modular multi-level converter that could apply to higher voltage levels with increasing the number of modular multi-level converter submodules. The conventional approach is based on constant DC voltage regulated by a shunt controller or uncontrolled DC voltage to mitigate system voltage sag utilizing series controller. However, their mitigation capability is circumscribed, compensating deeper and longer duration voltage sags for the limit of device capacity. In this article, the voltage sag compensation mechanism of the modular multi-level converter-unified power quality conditioner is analyzed. A constant active-current limit coordinated control scheme is proposed considering the compensation energy derived from both DC capacitors in the submodules and source side. No additional expended capacity devices are required, and the compensation energy is increased via restricting the active current value of the shunt modular multi-level converter. The coordinated control strategy is flexible and easy to implement. Experimental work and simulation results are provided to validate the effectiveness of the proposed approach in compensation of deep and long-duration voltage sags. © 2016 Taylor & Francis Group, LLC. Source

Yao Y.,University Of Science And Technology Liaoning | Bai Y.,University Of Science And Technology Liaoning | Liu M.,Rongxin Power Electronic Co.
Applied Mechanics and Materials | Year: 2013

The research object of this paper is about the oil equipments' fluid properties during spraying of the electrostatic spraying technology. Establishing the mathematical model of fluid inside the oiling machine in the process of computer simulation and using fluid dynamics analysis software (CFD) FLUENT to analyse numerical simulation within spraying fluid effectively. According to the actual situation, reach knife beam's pressure distribution, velocity distibution, flow trajectories, partial velocity diagram. Finally, verify the correctness and feasibility of the simulation by the contrast of the experimental and simulation data in the course of experiments. In view of the analysis and study of the electrostatic oiler internal fluid, it can be extended to the electrostatic spraying technology. The paper is supplement for further research of electrostatic spraying technology and data support for next step simulation analysis of loading of high-voltage electric field. © (2013) Trans Tech Publications, Switzerland. Source

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