Adaptive Reclosure Research Articles

Three-phase adaptive reclosure technology for half-wavelength transmission lines using residual voltage frequency difference to identify fault existence

• The single-phase reclosing technique should not be used in half-wavelength transmission systems. • The residual voltage of half wavelength transmission system can be used to determine the existence of faults. • The frequency difference of residual voltage can be used to determine the existence of faults. • We propose a complete and feasible three-phase adaptive reclosure scheme for half wavelength transmission system. UHV AC transmission lines use adaptive reclosure technology not only to avoid reclosing in the permanent faults, but also effectively prevent the emergence of reclosing overvoltage, adaptive reclosure is of great significance, and its technical principle is based on the study and judgment of the existence of the fault. The reactive power of half-wavelength transmission lines along the line was self-balanced, no shunt reactor equipment, there is no "beat frequency" phenomenon, and very little information is available after the three-phase trip. In this paper, we analyze the fault traveling wave's frequency characteristics and identify the fault's characteristics based on the residual voltage frequency difference of the line after the three-phase trip. After the disappearance of the line fault, the stable frequency difference obtained by CVT reflects the entire length of the line, which is not affected by the system boundary conditions and can complete the reliable identification of the disappearance of the line fault. The two-terminal criterion is given for the short-line dead zone problem, and then a three-phase adaptive reclosure scheme for half-wavelength transmission lines based on the frequency difference to identify fault disappearance is proposed. Extensive RTDS digital-analog hybrid tests show that the method is correct and robust.

Terminal voltage correlation-based adaptive reclosure strategy for VSC-MTDC grids

Auto-reclosure in VSC-MTDC grids has the defect of blindly reclosing. Research on adaptive reclosure strategies capable of identifying fault property and arc extinction time is essential to promote the reliability of power supply. This paper proposes a novel adaptive reclosure strategy for VSC-MTDC grids. At first, the terminal voltage is derivated by Marti model, which takes the distributed and frequency-dependent characteristics of the line parameters into account. The calculation result of the terminal voltage achieves high accuracy. Subsequently, a main criterion exploiting Pearson correlation coefficient between the calculated terminal voltage and the actual terminal voltage on the faulty line is proposed for identifying the fault property and the arc extinction time. Moreover, an auxiliary criterion utilizing the steady-state amplitude of the terminal voltage is added to further ensure the identification reliability of fault property. Finally, the effectiveness of the adaptive reclosure strategy is verified in PSCAD/EMTDC. The influencing factors and advantages of the proposed strategy are discussed and compared.

Three‐phase adaptive reclosure for transmission lines with shunt reactors using mode current oscillation frequencies

Three‐phase adaptive reclosure for transmission lines with shunt reactors using mode current oscillation frequencies

Application of artificial neural network (ANN) to enhance power systems protection: a case of the Nigerian 330 kV transmission line

This work investigates an improved protection solution based on the use of artificial neural network on the 330 kV Nigerian network modeled using MATLAB R2014a. Measured fault voltages and currents signals decomposed using the discrete Fourier transform implemented via fast Fourier transform are fed as inputs to the neural network. The output plots of the neural network shows its successful application to fault diagnosis (fault detection, fault classification and fault location). Unlike conventional protection schemes, the neural network can be adapted to distances which can cover the entire length of the protected line. Numerical assessment carried out on the neural network fault locator shows a reduced time of operation of 5.15 ms as compared to the 0.350 s with the use of ordinary numerical relays. This work also investigates the adaptive auto-reclosure scheme implemented using artificial neural network. The adaptive reclosure scheme has been adapted for use in the Nigerian network successfully to distinguish transient and permanent faults. Simulation results prove that the adaptive reclosure scheme was able to detect a line-to-ground transient fault and clear this fault in 0.1 s while the line-to-ground permanent fault is cleared after 0.14 s. The fault diagnostic algorithm designed using artificial neural network (ANN) for the 330 kV network was tested on a 132 kV network. Results show and prove that the algorithm is flexible and can be adopted to other networks.

The Study on Single-Phase Adaptive Reclosure of Transmission Lines with Series Capacitance

To solve the problem of single-phase adaptive reclose in line with series compensation, this paper proposes a criterion using the different frequency components belonged to the recovery voltage to defect transient faults and permanent faults. Firstly, this paper analysis the frequency characteristics after fault-phase circuit breaker tripped in single-phase ground fault, establishes the recovery voltage identification model including the DC component and each component. When single-phase-to-ground fault occurs and both sides of the circuit breaker open, the recovery voltage as a known quantity, each frequency component is obtained by least square fitting. The amplitudes of various frequency components are adopted to distinguish the permanent faults from transient faults. Through theoretical analysis and PSCAD simulation show that the criterion is correct and effective and can detect the nature of single-phase fault quickly.

Permanent Fault Identification Method for Single-Phasea Adaptive Reclosure of UHVAC Transmission Line

In order to avoid the UHVAC (Ultra High Voltage Alternating Current) transmission line with shunt reactor fault voltage smaller problems, through the analysis of single-phase permanent fault when tripping phase terminal voltage characteristics, this paper presents a fault phase voltage signal of the two order derivative and the original signal ratio of a new method for steady-state frequency discrimination single-phase permanent fault. The principle of this method is simple, and it can avoid the problem that the fault voltage caused by the installation of shunt reactor is small. The adaptability and correctness of the proposed method are verified by a large number of simulations.

An Adaptive Reclosure Scheme for Parallel Transmission Lines With Shunt Reactors

A new reclosure scheme applied to parallel transmission lines with shunt reactors is proposed to improve the adaptability of the autoreclosure. Detailed analysis of the fault phase voltage is performed to derive the criteria to distinguish the temporary fault from the permanent fault. For different types of ground faults, the integral of the fault phase's recovery voltage is used to identify the permanent grounded faults. For different types of cross-line ungrounded faults, the integral of the $\beta $ modulus of the fault phase's recovery voltage is used to identify the permanent cross-line ungrounded faults. Besides, the phase reclosure sequence principle is used for all fault types. The performance of the proposed scheme is verified by the digital and analog simulation test for a 500-kV parallel transmission line with shunt reactors for several cases on different fault types and fault conditions. The Electromagnetic Transients Program-based and physical analog simulation results show that the proposed scheme is effective.

An Adaptive Autoreclosure Scheme with Reference to Transient Stability for Transmission Lines

Autoreclosure provides a means of improving power transmitting ability and system stability. Conventional reclosure adopts the fixed dead time interval strategy, where the reclosure is activated after a time delay to restore the system to normal as quickly as possible without regard to the system conditions. However, these simple techniques cannot provide optimal operating performance. This paper presents an adaptive autoreclosure algorithm including variable dead time, optimal reclosure, phase-by-phase reclosure and emergency extended equal-area criterion (EEEAC) algorithm in order to improve system stability. The reclosure algorithm performs the operations that are attuned to the power system conditions. The proposed adaptive reclosure algorithm is verified and tested using ATP/EMTP MODELS, and the simulation results show that the system oscillations are reduced and the transient stability is enhanced by employing the proposed adaptive reclosure algorithm.

Identification of Permanent Faults for Three-phase Autoreclosing Using Inductance Parameter on Transmission Lines with Shunt Reactors

A novel method using mode component inductance parameter of shunt reactors is presented in order to identify temporary faults and permanent faults for three-phase adaptive reclosure on transmission lines with shunt reactors at both ends. The method uses π-type equivalent model as the prototype to build parameter identification formula. When some single phase-to-ground fault occurs, the parameter identification formula of zero-mode component is built; when some phase-to-phase fault occurs, the parameter identification formula of line-mode component is built. The current of the shunt reactor is given and the inductance of the shunt reactor is taken as the unknown parameter to evaluate the difference between the calculated inductance and the actual one so as to distinguish permanent fault from transient fault. The inductance difference of the temporary fault is minute because the actual fault model is consistent with the prototype. But the inductance difference of the permanent fault is distinct because the actual fault model is inconsistent with the prototype. Results of EMTP simulation show that the proposed method is reliable and effective, and can be applied to the three-phase adaptive reclosure on transmission lines with shunt reactors.

An Adaptive Reclosing Algorithm to Discriminate between Permanent Fault and Transient Fault using THD of Voltage Waveform

This paper presents a new adaptive single-phase auto reclosure (SPAR) algorithm to discriminate between a permanent fault and a transient fault and to minimize a protection dead time. The algorithm precisely detects the extinction of the secondary arc, based on THD's profiles on the faulted phase voltage waveform. The EMTP/ATPDraw program was used to simulate the single phase grounding fault for evaluating the proposed algorithm. And the simulation results show that the proposed algorithm is performing well.

A Novel Single-Phase Adaptive Reclosure Scheme for Transmission Lines With Shunt Reactors

Single-phase adaptive reclosure (SPAR) schemes applied to transmission lines have been an effective method to improve the stability of power system. Attractive techniques have been proposed for SPAR schemes based on the tripped fault-phase voltage. But for transmission lines with shunt reactors, the voltage is so minor that the error of voltage transformer limits the applications of voltage-based SPAR schemes. To overcome this disadvantage, a new scheme using differential current between the calculated current based on transient fault model and the actual measured current from the fault phase of shunt reactor is proposed in this paper. The calculated current is obtained by using the transient fault model whether there is a transient or permanent fault. In the case of transient fault, the calculated current is close to the measured current due to the actual fault model being close to the calculated model. As for the permanent fault, the calculated current is quite different from the measured current. Therefore, the differential current of the fault phase can be employed to distinguish permanent fault from transient fault. At last, the Alternative Transients Program simulation results show that the developed algorithm can identify the permanent fault correctly and reliably, and is promised to be applied to SPAR for transmission lines with shunt reactors.

Adaptive automatic reclosure of high voltage lines for elimination of interphase short circuits

The successive switching of the phases of lines with control of the induced voltage in the phases through three-phase automatic reclosure makes it possible to avoid switching on interphase short circuits, and in 2/3 of the cases of single phase faults, to avoid switching on short circuits in general. By using this method for testing aerial transmission lines it is also possible to avoid switching the three phases onto a short. Here it is unnecessary to make any significant changes in the functional protective circuits. The proposed method can be used on 330–750 kV aerial transmission lines, as well as on 110–220 kV aerial transmission lines that are equipped with phase controlled breakers and voltage transformers.

A new digital algorithm for adaptive reclosure of transmission lines

A new digital algorithm for adaptive reclosure of transmission lines

New concept in transmission line reclosure using high-frequency fault transients

The authors present a new concept: ‘adaptive optimal reclosure’ under transmission line faults by integrating the adaptive and optimal reclosure techniques. Simulation studies prove that the proposed technique is able to first detect the persistence time of fault path arc and then capture the optimal reclosure time, thereby enhancing system stability.