A new approach to reactive power calculation of the static VAr compensator

Author(s):  
Alexander Osnach
2020 ◽  
Vol 13 (3) ◽  
pp. 381-393
Author(s):  
Farhana Fayaz ◽  
Gobind Lal Pahuja

Background:The Static VAR Compensator (SVC) has the capability of improving reliability, operation and control of the transmission system thereby improving the dynamic performance of power system. SVC is a widely used shunt FACTS device, which is an important tool for the reactive power compensation in high voltage AC transmission systems. The transmission lines compensated with the SVC may experience faults and hence need a protection system against the damage caused by these faults as well as provide the uninterrupted supply of power.Methods:The research work reported in the paper is a successful attempt to reduce the time to detect faults on a SVC-compensated transmission line to less than quarter of a cycle. The relay algorithm involves two ANNs, one for detection and the other for classification of faults, including the identification of the faulted phase/phases. RMS (Root Mean Square) values of line voltages and ratios of sequence components of line currents are used as inputs to the ANNs. Extensive training and testing of the two ANNs have been carried out using the data generated by simulating an SVC-compensated transmission line in PSCAD at a signal sampling frequency of 1 kHz. Back-propagation method has been used for the training and testing. Also the criticality analysis of the existing relay and the modified relay has been done using three fault tree importance measures i.e., Fussell-Vesely (FV) Importance, Risk Achievement Worth (RAW) and Risk Reduction Worth (RRW).Results:It is found that the relay detects any type of fault occurring anywhere on the line with 100% accuracy within a short time of 4 ms. It also classifies the type of the fault and indicates the faulted phase or phases, as the case may be, with 100% accuracy within 15 ms, that is well before a circuit breaker can clear the fault. As demonstrated, fault detection and classification by the use of ANNs is reliable and accurate when a large data set is available for training. The results from the criticality analysis show that the criticality ranking varies in both the designs (existing relay and the existing modified relay) and the ranking of the improved measurement system in the modified relay changes from 2 to 4.Conclusion:A relaying algorithm is proposed for the protection of transmission line compensated with Static Var Compensator (SVC) and criticality ranking of different failure modes of a digital relay is carried out. The proposed scheme has significant advantages over more traditional relaying algorithms. It is suitable for high resistance faults and is not affected by the inception angle nor by the location of fault.


2014 ◽  
Vol 533 ◽  
pp. 397-400 ◽  
Author(s):  
Chi Jui Wu ◽  
Yu Wei Liu ◽  
Shou Chien Huang

To modify the power factor and balance the three-phase currents simultaneously, this paper proposes the instantaneous compensator to calculate the compensation current. The instantaneous compensator utilizes two-dimensional instantaneous space vector and setting the active power as a constant for each cycle which can improve power quality effectively. Moreover, the instantaneous compensator requires an independent power source, whose capacity can be reduce by using a static var compensator (SVC). An SVC does not interfere with the capability of the instantaneous compensator. Field measurement data were analyzed. Simulation results confirmed the feasibility of correcting the power factor and balancing load currents simultaneously using the proposed method.


2014 ◽  
Vol 536-537 ◽  
pp. 1527-1531
Author(s):  
Ya Feng Li ◽  
Zi Wei Zheng

The Series Dynamic Voltage Regulator can compensate the harmonics distortion caused by voltage type harmonic source This paper presents a new approach of detecting harmonic voltage in dq0 coordinates, based on the generalized instantaneous reactive power ,and used in the series dynamic voltage regulator successfully. It is demonstrated by theoretical analysis and simulation results that the proposed detecting method of harmonic voltage is correct and valid.


Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1643
Author(s):  
Jorge El Mariachet ◽  
Yajuan Guan ◽  
Jose Matas ◽  
Helena Martín ◽  
Mingshen Li ◽  
...  

The dynamic performance of the local control of single-phase voltage source inverters (VSIs) can be degraded when supplying to nonlinear loads (NLLs) in microgrids. When this control is based on the droop principles, a proper calculation of the active and reactive averaged powers (P–Q) is essential for a proficient dynamic response against abrupt NLL changes. In this work, a VSI supplying to an NLL was studied, focusing the attention on the P–Q calculation stage. This stage first generated the direct and in-quadrature signals from the measured load current through a second-order generalized integrator (SOGI). Then, the instantaneous power quantities were obtained by multiplying each filtered current by the output voltage, and filtered later by utilizing a SOGI to acquire the averaged P–Q parameters. The proposed algorithm was compared with previous proposals, while keeping the active power steady-state ripple constant, which resulted in a faster calculation of the averaged active power. In this case, the steady-state averaged reactive power presented less ripple than the best proposal to which it was compared. When reducing the velocity of the proposed algorithm for the active power, it also showed a reduction in its steady-state ripple. Simulations, hardware-in-the-loop, and experimental tests were carried out to verify the effectiveness of the proposal.


SIMULATION ◽  
2017 ◽  
Vol 93 (6) ◽  
pp. 515-525 ◽  
Author(s):  
Mohammad Reza Asban ◽  
Jamshid Aghaei ◽  
Taher Niknam ◽  
Mohammad Amin Akbari

This paper introduces a method for reducing damages arising from voltage fluctuations, voltage flicker, imbalance in the three-phase and power factor reduction caused by electric arc furnaces. A novel equation is defined to calculate the susceptance values of the static var compensator control system, the active power functions of phase load as well as the reactive power ones that have been used to suppress the voltage fluctuation. By compensating the impulsive part of active power component in the impulsive loads, not only can we reduce voltage fluctuations, flicker effects, balance the system and increase the power factor, but also voltage stabilization can be directly controlled. By studying this method and simulating on Electro-Magnetic Transients Program (EMTP) software, we can see that, according to the allowable flicker limit, a compensation method can balance the system, increase power factor and resolve the problem of voltage fluctuations and flicker.


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