Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid

Shenyang, China

Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid

Shenyang, China
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Xu J.,Shenyang University of Technology | Hao S.,Shenyang University of Technology | Lu Y.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid
2015 3rd International Conference on Electric Power Equipment - Switching Technology, ICEPE-ST 2015 | Year: 2015

Extra-high (EHV) transmission system has the characteristics of high voltage and large capacity, and a high amplitude current will be generated through the grounding line and ground net when failure occurs. Step voltage caused by the diffusion of fault current in soil is an important parameter affecting the normal operation of the system. The calculation and analysis of the step voltage in IEEE Std 80-2000 standard is rough, unable to reflect the soil surface potential distribution in substation comprehensively. This paper present an algorithm combined transmission line theorem and finite element analysis to calculate the electric potential distribution accurately, getting the attenuation law of surface potential and the step voltage. Analysis shows that the soil surface electric potential is well-distributed in normal operation and the step voltage is very small, only a dozen volt; The potential value can achieve kilovolt during short trouble and there will be a great attenuation within one meter; Soil resistivity, earth current amplitude and buried depth of ground net are the important factors influencing the surface potential distribution and step voltage. © 2015 IEEE.


Lin X.,Shenyang University of Technology | Wen M.,Shenyang University of Technology | Zhong S.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid
2015 3rd International Conference on Electric Power Equipment - Switching Technology, ICEPE-ST 2015 | Year: 2015

High temperature can cause many problems in OIP transformer bushing, such as aging of insulation and partial discharge, which will obviously reduce the lifetime of bushing. This contribution calculates the total loss in bushing under both voltage and current loads using the finite elements method(FEM) and then obtains the temperature distribution though the finite volume method (FVM). Computation results indicates that the total loss in 550kV bushing is 1203.89W, among which the 4.5% is dielectric loss. The peak value of temperature rise reaches 76.27 °C, which appears in the center pilot. Measurement of temperature rise is taken to check the calculation method, in which 16 points on the center pilot and nine points on the surface of umbrellas are taken into the comparison. Among the 25 compared points, error stays within 5% on 16 points, between 5% and 10% on 4 points, between 10% and 15% on three points. It can be concluded that the methods used in this contribution is proper and can support the designing and analyzing of OIP bushing. © 2015 IEEE.


Li B.,Shenyang University of Technology | Li B.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | Xu J.,Shenyang University of Technology | Xu J.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid
2013 2nd International Conference on Electric Power Equipment - Switching Technology, ICEPE-ST 2013 | Year: 2013

The lightning current might inject grounding grid through the grounding lead when the arrester suffered a lightning wave in substation. Then the ground potential difference(the difference of ground potential can/may) generated interference voltage on secondary cables due to earth potential rising. The interference voltage might lead secondary equipments misoperation and even damage. To analysis the problems mentioned above, a equivalent circuit model was established. The transient voltage caused by ground potential difference to secondary cables could be (can be or is) calculated by EMTP-ATP. As a validation, the impulse voltage generator was used as voltage source to simulate that substation encountered with the lightning, and to measure the interference voltage at cable terminal as well. Both experiment and computer simulation had been taken to analysis the influencing factors of the interference voltage on secondary cables and the ports of secondary equipments. The factors included the lightning current injection point and the soil resistivity rate. The analysis would provide a reasonable reference for wiring cables to improve anti-jamming capability of secondary equipments in substation. © 2013 IEEE.


Xia Y.,Shenyang University of Technology | Xia Y.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | Xu J.,Shenyang University of Technology | Xu J.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | And 4 more authors.
2013 2nd International Conference on Electric Power Equipment - Switching Technology, ICEPE-ST 2013 | Year: 2013

According to the mechanical failure of Gas Insulated Switchgear (GIS) in the earthquake will cause a great loss to the power system. This paper, by using the three-dimension design software to build a geometric model of 420 kV GIS, by using the finite element analysis method to make the mode analysis, and then acquired structural frequencies and mode features of the GIS, and by using spectral analysis to get the stress distribution and structure deformation in the case of IX degree earthquake based on it. Through the simulation result of this model, the structure of the maximum stress occurs at the bracket where connected bus, and the maximum stress is 17.5Mpa that far less than the yield limit that is 235MPa. The maximum deformation occurs in the middle of the bus, and the maximum deformation is only 0.86 mm/m that comply with the requirements of the bus deformation is less than 3 mm/m. The results can provide a reference for the seismic reliability analysis of the high-voltage switchgear equipment. © 2013 IEEE.


Yang Z.-Z.,Shenyang University of Technology | Yang Z.-Z.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | Xu J.-Y.,Shenyang University of Technology | Xu J.-Y.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid
2013 2nd International Conference on Electric Power Equipment - Switching Technology, ICEPE-ST 2013 | Year: 2013

A kind of monitoring and recording system of mechanical characteristics of high voltage circuit breaker is designed in this paper. The system that has the characteristic with microsecond single point acquisition speed and microvolt level amplitude resolution can collect information data of different mechanical characteristics of high voltage circuit breaker and automatic distinguishing data to fault category to establish the correct information and fault information database, and can monitor seven kinds of mechanical characteristics that include displacement, vibration, current of energy storage motor, current of opening/closing release coil, current of permanent magnet coil, voltage of permanent magnet coil of high voltage circuit breaker with the spring operation mechanism or the permanent magnet operation mechanism, and so on. The system can analysis time domain and frequency domain waveform with wavelet analysis method that have characteristics of multi-resolution analysis, and the ability of characterization the partial information of time domain and frequency domain signal for mechanical characteristics of high voltage circuit breaker. That make the target signal frequency division for removing high frequency noise to get pure signal waveform. The waveform can reflect trend of mechanical movement characteristics of high voltage circuit breaker accurately and clear. © 2013 IEEE.


Teng Y.,Shenyang University of Technology | Teng Y.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | Wang Y.,Shenyang University of Technology | Wang Y.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | And 2 more authors.
2013 2nd International Conference on Electric Power Equipment - Switching Technology, ICEPE-ST 2013 | Year: 2013

Based on the new motor operating mechanism of high voltage circuit breaker, a set of permanent magnet brushless DC(PMBLDC) motor is designed, and an operating mechanism control device, of which the core is the digital signal processor (TMS320F28335 DSP), is built. And control technology of pulse width modulation is applied. By detecting contact displacement, and changing the duty ration simultaneously, the problems that the contact speed of 126kV high voltage circuit breaker is uncontrollable and that at the ending of dividing and connecting, the machinery collides intensively will be solved. The online test on 126kV vacuum circuit breaker shows that the operating mechanism of the PMBLDC motor drives high voltage circuit breaker through PWM technique, which can achieve the aim of controlling the speed of the high voltage circuit breaker contact and improving the reliability of circuit breaker's operation. © 2013 IEEE.


Li H.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | Li H.,Shenyang University of Technology | Lin X.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | Lin X.,Shenyang University of Technology
2013 2nd International Conference on Electric Power Equipment - Switching Technology, ICEPE-ST 2013 | Year: 2013

According to an independent-developed motor operating mechanism of 126kV circuit breaker, the dynamic behavior was studied by simulation and experiment methods simultaneously. In this research, mathematical model of the actuator was established and dynamic load characteristics including equivalent moment of inertia and dynamic counter-force were analyzed in detail. Meanwhile, relationship between stroke of moving contact and rotating angle of driving motor was derived strictly. Based on the analyses above, transient magnetic field and dynamic parameters of driving motor were simulated by employing coupled field-circuit method which took the end winding leakage inductance into consideration. Opening and closing operation experiments were carried out by using the established test platform which combined motor operating mechanism with vacuum circuit breaker. The test results indicated that motor operating mechanism could be able to achieve opening and closing operation of 126kV vacuum circuit breaker reliably. The average closing velocity and opening velocity could reach 2.37m/s and 3.31m/s respectively, which totally met the requirement of vacuum circuit breaker. Simulation analyses of dynamic characteristics were in agreement with test results well. That verified the validity of the simulation analyses. © 2013 IEEE.


Liu A.M.,Shenyang University of Technology | Liu A.M.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | Yang Y.H.,Shenyang University of Technology | Yang Y.H.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | And 2 more authors.
2013 2nd International Conference on Electric Power Equipment - Switching Technology, ICEPE-ST 2013 | Year: 2013

Due to short working hours and high action speed, the permanent magnetic actuator of high voltage circuit breaker would generate eddy current in the dynamic and static iron core when it was working. The eddy current would weaken magnetic field of the permanent magnet, which had a great impact on the characteristics of actuator. The coupling method was used to analyze the transient magnetic field of permanent magnetic actuator, the transient magnetic field supplied by voltage was studied and the mathematical model of the nonlinear transient magnetic field was deduced considering the impact of eddy current. Finite element software Ansoft was used to simulate the square permanent magnetic actuator. The influence of eddy current on the characteristics of permanent magnetic actuator was analyzed and studied, and its loss was calculated and analyzed. The changes of electromagnetic force, speed, action time and other parameters of permanent magnetic actuator with different materials and structures was comparative analyzed. The calculation results show that the action time of permanent magnetic actuator will increase for the effect of eddy current. In the operational process of permanent magnetic actuator, the eddy current loss of the dynamic and static iron core is great. At the same time the rational design of the dynamic and static iron core can also greatly reduce the eddy current loss. The study of permanent magnetic actuator's characteristics taking the influence of eddy current into account can provide theoretical basis for its reasonable design. © 2013 IEEE.


Cao C.,Shenyang University of Technology | Cao C.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | Lin X.,Shenyang University of Technology | Lin X.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid
2013 2nd International Conference on Electric Power Equipment - Switching Technology, ICEPE-ST 2013 | Year: 2013

For researching dynamic characteristics of circuit breakers(CB), aiming at a 12kV vacuum circuit breaker(VCB) with permanent magnetic actuator, the dynamic model of the vacuum circuit breaker is built based on virtual prototype technology. According to D' Alemhert's movement equations and Maxwell electromagnetic equations, the simulation is made on the vacuum circuit breaker in opening and closing dynamic processes. The experimental system is designed in order to verify simulation results. The opening time and the closing time of simulative model are 40.3ms and 55.2ms, simulative results are in accord with experimental data. Influencing factors of the closing bouncing and action principles of these factors are analyzed by dynamic simulation on the closing bouncing process. Analytic results indicate that increasing the preload and the stiffness coefficient of contact spring can limit the closing bouncing. © 2013 IEEE.


Wang F.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | Wang F.,Shenyang University of Technology | Lin X.,Liaoning Province Key Laboratory of Safe Operation and Monitoring of Power Grid | Lin X.,Shenyang University of Technology | And 6 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2012

In order to improve the accuracy of calculation of UHV system transient voltages, taking ultra-high voltage switching substation in China as example, we established a model symbolizing the transmission characteristics of hybrid gas insulated switchgear (HGIS) enclosure on the basis of theory of the multi-conductor transmission lines and phase-mode transformation method. In addition, using π-type equivalent circuit to express grounding unit and combining with internal HGIS transient model, we calculated the very fast transient over-voltage (VFTO) and transient enclosure voltage (TEV) produced by operation of disconnector. On the one hand, we analyzed VFTO of key equipment at HGIS and the maximum values and spectral characteristics of TEV, on the other hand, we analyzed the effects of different shell grounding and grounding network on the TEV and VFTO. The results show that, while considering the case of grounding network, the peak value of VFTO is 1296 kV, and the peak value of TEV is 83 kV, which are lower than those without considering grounding network. A proper grounding is effective way to reduce the transient voltage of UHV HGIS system. The calculation and research results could be used as reference for electrical design of HGIS and relative electric devices.

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