For HVDC transmission system, the smoothing reactor has two structural types; oil-immersed core reactor and air-core reactor. The former needs to concentrate installed on DC-line, and the latter can be arranged flexib...
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For HVDC transmission system, the smoothing reactor has two structural types; oil-immersed core reactor and air-core reactor. The former needs to concentrate installed on DC-line, and the latter can be arranged flexibly on both pole line and neutral line. According to the different arrangements of smoothing reactors, the system steady-state performance and over-voltage of converter station have some difference. In this paper, the influence of different smoothing reactor arrangements on the system steady-state performance and converter station over-voltage performance of Xiluodu-Guangdong ± 500kV double-circuit HVDC project is analyzed by using ATP/EMTP. A reasonable arrangement of smoothing reactor is proposed, which aims at both maintaining reliability and reducing costs.
Icing of overhead power lines is a serious problem for electric utilities. Among various deicing approaches, short circuit based de-icing is one of the most frequently used approaches. Whereas, formation of short circ...
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ISBN:
(纸本)9782858730810
Icing of overhead power lines is a serious problem for electric utilities. Among various deicing approaches, short circuit based de-icing is one of the most frequently used approaches. Whereas, formation of short circuit based de-icing scheme is not a simple task since transmission lines are tripped and system topology varies notably in ice storm. Based on thorough investigation of pre-established de-icing schemes, rules to set up de-icing schemes are concluded. An expert system combining the power of graph theory has been developed in the paper to enumerate all ice-melting paths. Based on the ice-melting paths enumerated by the system, dispatch staffs can form optimal de-icing scheme easily.
Direct current transformer is the key device in measuring high current value of HVDC power system. Its accuracy and reliability is an important basis guaranteeing the control and protection system of HVDC grid work no...
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Direct current transformer is the key device in measuring high current value of HVDC power system. Its accuracy and reliability is an important basis guaranteeing the control and protection system of HVDC grid work normal. A mal-operation event of protection relay of plusmn500 kV HVDC system of chinasouthernpowergrid Co., Ltd. is described. Measurement performance of optic-electric DC current transformer based on shunt measurement theory is analyzed. With the consideration of skin effect and close effect, the electro magnetic simulation about shunt is carried out. A series of frequency-dependent impedance tests about shunt in converter station are done too. The results of electro-magnetic simulation and in converter station tests are match. The research results show that the impedance of shunt will increase as the signal frequency goes high. High frequency signal will influence the measurement performance directly. Some methods of anti- interference are put forward at the end of this paper.
As more and more users require the microprocessor protection device has Ethernet interface based on IEC61850, a newly developed relay protection equipment based on DSP with Ethernet communication interface is introduc...
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As more and more users require the microprocessor protection device has Ethernet interface based on IEC61850, a newly developed relay protection equipment based on DSP with Ethernet communication interface is introduced. The hardware circuit design, drive program and TCP/IP protocols are developed in detail to explain how to realize the Ethernet communication. We use DSP TMS320VC33 as the hardware platform and RTL8019AS as the Ethernet control chip. RTL8019AS is connected with DSP by (complex programmable logic device) CPLD. The integral layer model for Ethernet communication is a seven layers model based on IEC61850. The transport layer uses UDP protocol to transport data, as it is faster and more efficient. It can finish the Ethernet communication task and switch to other tasks by sending out and releasing signals to DSP. Experiment shows that it can satisfy HOkV line and below voltage relay protection's technology requirement to Ethernet communication successfully.
Based on the price elasticity matrix, the method to implement peak-valley and time-of-use and season-of-use price is explored to consist with electricity consumers' response of different industries. Through the es...
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Based on the price elasticity matrix, the method to implement peak-valley and time-of-use and season-of-use price is explored to consist with electricity consumers' response of different industries. Through the establishment of the season-of-use price elasticity matrix and time-of-use price elasticity matrix for each industry, the cost function and profit function for each industry are created according to the investigation data of electric power consumers. By solving the two functions' cross point, the needed adjustment ratios for each industry electricity consumers when achieving the electricity quantity shift limit with the electricity quantity shift cost restraint are obtained. At last, the proposed method is applied to Yunnan power system. The application results show the larger price adjustment quantity differences among the different industries when achieving the electricity quantity shift limit, and the necessity to implement different peak-valley and time-of-use and season-of-use prices in view of different electricity consuming characteristics of every industry.
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