Wide-Area Backup Protection Algorithm Research Articles

A wide area backup protection algorithm based on fault current comparison and evidence theory fusion

Abstract Wide-area backup protection using information in the area to determine the fault location comprehensively requires a high fault tolerance ability. However, the traditional wide area backup protection algorithm based on evidence theory assigns a separate value to each adjacent line for its fault probability, and the performance of the algorithm degrades in the condition of more information loss or errors. To solve these problems, this paper proposed a wide area backup protection algorithm based on fault current comparison and improved evidence theory fusion. The proposed method first selects the suspected fault lines by sequence voltage sorting. Then, the information on the fault current sequence component and traditional protection action is collected and preprocessed to form the evidence set, and its basic probability assignment is calculated. Finally, the improved evidence theory is used for fusion to identify fault lines. Simulation results show that the algorithm can accurately identify fault lines under complex operating conditions, multiple information loss and errors, and has high fault tolerance.

An Adaptive Coordinated Wide-Area Backup Protection Algorithm for Network Topology Variability

An Adaptive Coordinated Wide-Area Backup Protection Algorithm for Network Topology Variability

Integrated Wide-Area Backup Protection Algorithm During Stressed Power System Condition in Presence of Wind Farm

Stressed power system conditions such as power swing, voltage instability and load encroachment may influence the secure operation of conventional backup protection at their third zone (zone 3). In this paper, a new integrated backup protection algorithm for distance relay is proposed based on wide-area measurements to distinguish the fault-stress conditions in the presence of offshore wind farm (WF). Presence of WF creates problem for distance relay due to varying wind speed and wide fluctuations in voltage and current signal during fault condition. In this work, two criteria are proposed to analyze and to identify the events. The first criterion compares the positive-sequence bus voltages in order to identify the faulty bus. According to second criterion, the absolute positive-sequence impedance angle difference between the lines connected to that faulty bus is computed to identify the faulty line. Numerous test cases with the WSCC 3-machine, 9-bus and IEEE 39 bus power system models have been simulated using EMTDC/PSCAD software. Results for different fault cases, power swing, load encroachment and voltage instability, and various non-fault cases like capacitor switching, demonstrate the efficacy of the wide-area backup protection scheme. Comparative assessment reports with the existing methods are also presented.

Research on a Distance Relay-Based Wide-Area Backup Protection Algorithm for Transmission Lines

In this paper, a distance relay-based wide-area backup protection (WABP) algorithm for transmission lines is presented. The proposed WABP collects the statuses of zone 2 and zone 3 distance relays in local substation and immediate neighboring substations. When a fault has occurred, the WABP decides whether the fault is on the protected transmission line or somewhere else. Then, it determines the appropriate time delay of tripping and acts in coordination with conventional distance relays. With the proposed WABP equipped, the setting of conventional distance relays can be simplified. The requirement of coordination between the conventional relays can be loosened and the difficulty of setting calculation can be reduced. Simulation results show that the proposed WABP can coordinate with conventional distance relays set by different methods, and it can correctly detect faults and help to reduce blackout area with fault tolerance.

A Wide-Area Backup Protection Algorithm Based on Distance Protection Fitting Factor

In view of the time delay and potential information loss problem in wide-area data acquisition, a wide-area backup protection algorithm based on the distance protection fitting factor is proposed in this paper. First, the contribution of the distance protection operating information to fault identification is defined as the distance protection contribution degree. Second, the protection fitness function and protection fitness expectation function are constructed using the distance protection contribution degree as the weight. And then, the distance protection fitting factor is gained by calculating the division of the protection fitness function by the protection fitness expectation function. Thus, the fault line can be identified. Finally, simulation tests on the IEEE 10-machine 39-bus system and Guizhou Duyun real-time digital simulator verify that the proposed method is not affected by the time delay in wide-area data acquisition and is able to identify the fault line correctly even when a large amount of distance protection operating information is lost or in error. Meanwhile, the uncertainty problem in traditional weight setting due to reliance on subjective experience is avoided. Besides, being small in computation amount, the proposed method is easy to implement in engineering practice.

Wide area backup protection algorithm for transmission lines based on fault component complex power

In this paper a new wide area backup protection algorithm based on the fault component complex power is proposed to overcome the problem of maloperation of conventional backup protection in highly stressed conditions of power system operation. Firstly, suspected faulty lines are detected using measured values of fault component voltages known as faulted area identification (FAI) criteria. Then, the fault component voltages and currents provided by phasor measurement units (PMUs) are applied to calculate the injected complex power to both terminals of the suspected faulty lines. The ratio between sum and difference of injected complex power to the both terminals of the suspected faulty lines is used as faulted line identification (FLI) criteria. The simulation studies performed on the IEEE 10 generator 39-bus system verify effectiveness of the proposed algorithm under various conditions and fault types.

Association Analysis of System Failure in Wide Area Backup Protection System

Abstract Wide area backup protection algorithm based on fault component identification is the heart of the whole wide area backup protection system, its validity and reliability is a problem which needs to be first considered in the engineering practice applications of wide area backup protection system. Wide are backup protection algorithm mainly use two kinds of wide area information to realize protection criterion, one is electrical quantity information, such as voltage, current, etc. Another one is protection action and circuit breaker information. The wide area backup protection algorithm based on electrical quantity information is mainly utilizing the significant change of electrical quantity to search fault component, and the primary means include current differential method of wide area multi-measuring points, the comparison method of calculation and measurement, the multiple statistics method. In this paper, a novel and effective association analysis of system failure in wide area backup protection system will be discussed carefully, and the analytical results are successful and reliable.

A Wide-Area Backup Protection Algorithm for Multi-Fault Location in Complex Large Power Grid

This paper presents a fitting degree-based multi-fault location algorithm for complex large power grid utilizing wide-area information. Firstly, fault injection current of the equivalent fault points is used in the equivalent model. Then the correlation matrix is formed by the network topology and associated nodal injection current and a network is formed to determine the location of faults. When multiple faults occur, the addition of the current of each two fault lines is calculated and the real-time current is measured. Then by calculating the minimum of fitting degree between two current values, fault line and virtual fault location can be determined. The simulation results of 10-generator 39-bus system verify the validity and feasibility of this algorithm.

A novel wide-area backup protection based on fault component current distribution and improved evidence theory.

In order to solve the problems of the existing wide-area backup protection (WABP) algorithms, the paper proposes a novel WABP algorithm based on the distribution characteristics of fault component current and improved Dempster/Shafer (D-S) evidence theory. When a fault occurs, slave substations transmit to master station the amplitudes of fault component currents of transmission lines which are the closest to fault element. Then master substation identifies suspicious faulty lines according to the distribution characteristics of fault component current. After that, the master substation will identify the actual faulty line with improved D-S evidence theory based on the action states of traditional protections and direction components of these suspicious faulty lines. The simulation examples based on IEEE 10-generator-39-bus system show that the proposed WABP algorithm has an excellent performance. The algorithm has low requirement of sampling synchronization, small wide-area communication flow, and high fault tolerance.

Correction to “Wide-Area Backup Protection Algorithm Based on Fault Component Voltage Distribution” [Oct 11 2752-2760

In the above titled paper (ibid., vol. 26, no. 4, pp. 2752-2760, Oct. 2011), Figs. 1 and 2 appear incorrectly. The correct figures are presented here.

Wide-Area Backup Protection Algorithm Based on Fault Component Voltage Distribution

A new wide-area backup protection algorithm based on the fault component voltage distribution is proposed in this paper. It is helpful to overcome the problems of complex setting and maloperation under flow transfer of conventional backup protection. The measured values of fault component voltage and current at one terminal of the transmission line are applied to estimate the fault component voltage at the other terminal. Then, the fault element can be identified by the ratio between the measured values and the estimated values. In addition, the speed of fault element identification can be accelerated by a faulted area detection scheme. The proposed method has the advantage of easy setting and low requirement for synchronized wide-area data. The studies performed on the IEEE 39-bus system validate the proposed algorithm under various faults and flow transfer.

A Fault Steady State Component-Based Wide Area Backup Protection Algorithm

A novel wide area backup protection algorithm to identify fault branch based on the fault steady state component is proposed. Under normal conditions of the power system, subsets of buses called protection correlation regions (PCRs) are formed on the basis of the network topology and phasor measurement unit (PMU) placement. After the fault occurs, by analyzing the fault steady state component of differential current in each PCR, the fault correlation region is confirmed and then a fault correlation factor (FCF), is calculated in real time to locate the fault branch. The simulation results for the 10-generator 39-bus system verify that this method is able to easily identify fault branch with limited measurement points.