The Comparative Analysis of SVC and STATCOM on Subsynchronous Oscillation Mitigation

The methods for subsynchronous oscillation mitigation based on SVC and STATCOM are analyzed in this paper. According to the IEEE first benchmark model, the electrical damping coefficients respectively provided by SVC and STATCOM connected at the generator terminal, as well as positive damping condition, are deduced by complex torque coefficient approach. Correlative factors which influence the two positive dampings are compared. The analysis results indicate that the positive damping provided by SVC is proportional to the size of system voltage. The positive damping provided by STATCOM is not affected by the size of system voltage, which is mostly proportional to the subsynchronous voltage produced itself. The controllers of SVC and STATCOM are designed and the positive dampings separately offered by SVC and STATCOM are optimized by phase compensation with test signal method. The time domain simulation reveals that STATCOM has stronger damping ability than SVC in the case of short circuit fault.

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Damping Analysis of Subsynchronous Oscillation Caused by HVDC

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.732-733.1065 ◽

2013 ◽

Vol 732-733 ◽

pp. 1065-1068

Author(s):

Shi Wu Xiao ◽

Lan Lan Shu

Keyword(s):

Time Domain ◽

Test Signal ◽

Subsynchronous Oscillation ◽

High Voltage Direct Current ◽

Damping Characteristics ◽

Torque Coefficient ◽

Machine Systems ◽

Electrical Damping ◽

The Time Domain ◽

Signal Method

High Voltage Direct Current transmission (HVDC) will cause torsional interaction under certain conditions. Among a variety of factors, improper rectifier control has fateful effect. In the paper, the test signal method which is the time-domain form of the complex torque coefficient approach (CTC approach) is studied. Its application conditions in multi-machine systems are summarized. Using the test signal method, impacts of DC power, DC voltage, rectifier controller parameters and generator output on electrical damping characteristics in the Suizhong system are studied based on time-domain simulation model.

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Damping Characteristics Analysis Based on Complex Torque Coefficient Method in Sub-Synchronous Oscillations

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.971-973.988 ◽

2014 ◽

Vol 971-973 ◽

pp. 988-991

Author(s):

Han Chen ◽

Chun Lin Guo

Keyword(s):

Large Scale ◽

Power Transmission ◽

Test Method ◽

Long Distance ◽

Damping Characteristics ◽

Torque Coefficient ◽

Synchronous Oscillations ◽

Electrical Damping ◽

The Time Domain ◽

Coefficient Method

Because of China's energy and load imbalance, large-scale long-distance power transmission becomes inevitable. Under this background , series compensation capacitor in the power system and HVDC developed rapidly, and the SSO (Sub-synchronous oscillations) caused by HVDC is becoming increasingly apparent. Fundamental reason of SSO lies in the sub-synchronous system negative damping characteristics, so it is necessary to analyze the system damping characteristics. The net system damping includes mechanical and electrical damping. Based on small-signal test method-complex torque coefficient method in the time-domain simulation , paper analyzed the system electrical damping and mechanical damping characteristics.

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Shafting Torsional Vibration Analysis of 1000 MW Unit under Electrical Short-Circuit Fault

Applied Sciences ◽

10.3390/app11199205 ◽

2021 ◽

Vol 11 (19) ◽

pp. 9205

Author(s):

Honggang Pan ◽

Yunshi Wu ◽

Zhiyuan Pang ◽

Yanming Fu ◽

Tianyu Zhao

Keyword(s):

Short Circuit ◽

Power Grid ◽

Two Phase ◽

Shaft System ◽

Three Phase ◽

Speed Fluctuation ◽

Grid Side ◽

Generator Terminal ◽

The Impact ◽

Short Circuit Fault

Taking a 1000 MW turbine generator as the research object, the short-circuit fault in electrical disturbance is analyzed. Since it is very difficult to carry out fault analysis experiments and research on actual systems, simulation analysis is one of the more effective means of electrical fault diagnosis; the simulation’s results approach the actual behavior of the system and are ideal tools for power system analysis, and can provide an empirical basis for practical applications. The short-circuit fault model of the SIMULINK power system is built to analyze the two types of faults of generator terminals short-circuit and power grid short-circuit. The impact load spectrum, fault current and speed fluctuation between low-voltage rotors were extracted and analyzed. The conclusion is that the impact value of electromagnetic torque at the generator terminal is greater than that on the power grid side. The impact value of a two-phase short-circuit at the generator terminal is the largest, and that of a three-phase short-circuit on the power grid side is the smallest. The transient impulse current of a three-phase short-circuit at any fault point is greater than that of a two-phase short-circuit; the impulse current of the grid side short-circuit is much greater than that of the generator terminal short-circuit; the speed fluctuation and fluctuation difference caused by the three-phase short-circuit in the grid side are the largest. The alternating frequency of the transient electromagnetic force of the four kinds of faults avoids the natural frequency of the torsional vibration of the shaft system, and the torsional resonance of the shaft system in the time domain of the short-circuit fault will not appear. However, after the fault is removed, the residual small fluctuation torque in the system has a potential impact on the rotor system. This research shows an analysis of the structural integrity and safe operation of turbine generator units after a short-circuit fault, which can not only be applied to engineering practice, but also provide a theoretical basis for subsequent research.

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Study on Dynamic Response of Torsional Vibration of Turbo-Generator Unit Caused by Short Circuit Fault

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.566.248 ◽

2012 ◽

Vol 566 ◽

pp. 248-252 ◽

Cited By ~ 1

Author(s):

Cheng Bing He ◽

Dong Chao Chen ◽

Yu Jiong Gu

Keyword(s):

Torsional Vibration ◽

Short Circuit ◽

Dynamic Responses ◽

Stable Operation ◽

Two Phase ◽

Time Frequency ◽

Turbo Generator ◽

Complex Morlet Wavelet ◽

Generator Terminal ◽

Short Circuit Fault

When short circuit faults happen near power plant or generator terminal, severe transient torque shock will act on the shaft system, which seriously affects the safe and stable operation of the unit. Using the increment transfer matrix method, the dynamic responses of torsional vibrations are calculated in this work. Combined with the complex Morlet wavelet and time-frequency contour map, the time-frequency domain characters of dynamic torque are analyzed. The analyzed results show that the torque value caused by three phase short circuit fault is largest. The order of torque value from high to low is two phase short circuit to ground, two phase interphase short circuit and single phase short circuit. The electric distance between short circuit point and generator is more short, and the torsional vibration is more serious.

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Sub-Synchronous Oscillation Caused by HVDC and the Damping Characteristic Analysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.971-973.1353 ◽

2014 ◽

Vol 971-973 ◽

pp. 1353-1356

Author(s):

Han Chen ◽

Chun Lin Guo ◽

Qin Lei Chen

Keyword(s):

Large Scale ◽

Power Transmission ◽

Test Method ◽

Characteristic Analysis ◽

Long Distance ◽

Damping Characteristics ◽

Torque Coefficient ◽

Electrical Damping ◽

The Time Domain ◽

The Impact

Because of China's energy and load imbalance, respectively, large-scale long-distance power transmission becomes inevitable. Under this background , HVDC develops rapidly, SSO (Sub-synchronous oscillations) caused by HVDC is becoming increasingly apparent. The sub-synchronous electrical damping within the frequency range is difficult to calculate. Based on small-signal test method-complex torque coefficient method in the time-domain simulation , the paper calculated the sub-synchronous electrical damping characteristics of the system and analyzed the impact of the unit interaction, DC power and the generator output on sub-synchronous electrical damping characteristics.

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Identification of Lightning Strikes on Transmission Lines Based on Integral Method and Wavelet Analysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.936.2190 ◽

2014 ◽

Vol 936 ◽

pp. 2190-2195

Author(s):

Hong Wei Yan ◽

Yong Li Zhu ◽

Guo Chen Fan ◽

Xi Xiong

Keyword(s):

Transmission Lines ◽

Short Circuit ◽

Transient Current ◽

Scale Transformation ◽

Current Waveform ◽

Lightning Strikes ◽

Multi Scale ◽

Measuring Devices ◽

The Time Domain ◽

Short Circuit Fault

Transient signals caused by lightning strikes on transmission lines may interfere with the distance measuring devices relying on traveling wave. A synthesized method based on the additional components of disturbed current is proposed to distinguish between lightning interference, lightning fault and short-circuit fault. Firstly, since the disturbed current waveform generated by lightning interference and faults are distinct in the time domain, transient current components over and below timeline are respectively integrated to identify lightning interference from faults. And then, due to the distribution differences of current in the frequency domain, multi-scale transformation of wavelet is adopted to analyze the energy spectrum of transient current generated by short-circuit fault and faults of lightning. Numerous PSCAD simulation results demonstrate the proposed method is valid and correct.

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