A Fast Algorithm of the Apparent Factor Calculation for Distance Relay Setting without Fault Analysis

Maintaining selectivity among protective devices in interconnected power systems is of crucial importance. Therefore, it is necessary to install distance relays on both ends of the transmission lines to ensure efficient main and backup protection of the system. In this study, the zones and tripping time settings of distance relay for phase and ground protection of interconnected power systems are set and implemented in the professional DIgSILENT PowerFactory software. The interconnected test system IEEE 9-bus test system is used to validate the proposed methodology. The obtained results have approved that the setting and coordination of distance relays ensure adequate system protection against various fault types and locations.

Enhanced real time coordination of distance and user defined over current relays

This paper proposes an adaptive characteristic for eliminating the adverse effects of fault resistance and static synchronous compensator (STATCOM) on the performance of distance relays in transmission line and collector lines of doubly-fed induction generator (DFIG)-based wind farms in the case of single-phase-to-ground resistive faults. The proposed method improves the performance in distance relaying and maintains the coordination between relay pairs in the transmission line and wind farm collector lines. In this method, an adaptive coefficient that can modify the zone settings of conventional distance relays is added to their characteristic to improve the accuracy and coordination under the mentioned conditions. Using analytical relationships and numerical results from simulations in Matlab/Simulink environment, the efficiency of the proposed method is confirmed.

The loadability limits of distance relays are one of the most critical aspects of distance protection. This technical paper has presented the reader with valuable concepts on how to calculate the loadability limits of a distance relay and clarifies a lot of the ambiguity provided by current literature. The relay engineer should now be able to follow the steps on this paper along with NERC recommendations and be able to verify load encroachment problems before distance relay settings are applied.

Change in network structure or operating condition in a power system affects the impedance as calculated by distance relay during fault. Such changes may lead to malfunction of distance relay at times. In this paper an adaptive distance relay setting method using local data is proposed to prevent zone-1 malfunction following structural and operational changes. The performance of proposed adaptive setting method is tested on 39-bus New England system and a generic 12-bus power system using PSCAD/EMTDC simulation data and a comparative assessment is also provided.

This paper presents a scheme of distance protection for a renewable energy plant in electric power distribution systems. In many developing countries where renewable energy power plants are typically located in rural remote areas, they must be connected to weak power distribution systems inevitably. Although over-current relays are used to protect feeders at substations, fuses are only available elsewhere along feeder lines. To secure the system operation, distance protection is assigned to protect feeders. In this paper, distance relays are placed in the feeder along with over-current relays and fuses. Design of the distance protection of multi-source systems is described. This study considered the system consisting of a renewable energy plant. The power plant was a 6-MW unit of firmed power generation. The test feeder was simplified to be an equivalent four-bus test feeder for relaying purpose. Fault analysis in this paper was performed by using PowerWorld™ software. Obtained fault currents were used to establish protective zones of distance relays. In addition, this paper also compared the result of using distance protection with those of using directional over-current protection. As a result, protection of the power feeder with renewable power plants by using distance relaying can reduce complication in relay setting due to the impedance-based setting of the distance relay.

The opportunity for distributed generators to be connected to the power system has been increasing since the introduction of electricity deregulation. Moreover, a power system which has a new concept such as a micro-grid or a smart-grid is going to appear. The increase in the uncertainty of power flow and the power system operation under an irregular system configuration is supposed in such new power systems. And the sensitivity of a protection relay may decrease or a protection relay may miscoordinate with other protection relays. Under the above conditions, to prevent the fault expansion is required of the electric power utilities. From the background, the development of a program that can check the relay setting and the coordination between protection relay systems is desired.The development of “Support System for Setting and Coordination between protection relays” called SSSC was initiated in 2006, and it will be completed in 2011. SSSC has the following features;·It enables us to check whether the protection relay is set as operate correctly against all of assumed system faults.·It enables us to check automatically whether the coordination between the protection relays is proper as prevent the fault extension even if an unexpected condition occurs.·It enables us to analyze the response of the protection relays in the power system where some apparatus with nonlinear characteristic is installed.This paper describes the prototype of the SSSC based on the dynamic analysis like Y-method. Furthermore, in this paper, the checking method of coordination between protection relays for short circuit fault, and the verification results of the prototype in the 6.6kV model distribution system are described.

The development of Pesanggaran Conventional Substation into the Pesanggaran GasInsulated Switchgear (GIS) as a form of increasing the reliability of the electric power system inBali which led to changes in the protection system configuration on the transmission lineconnecting the GIS Pesanggaran and Nusa Dua Substation. The distance relay that waspreviously functioning as a primary protection was changed to backup protection due to the lackof selectivity of the distance relay in isolate the disruption and as the backup protection if themain protection experiencing a failure. Simulation testing using power system analysis softwareafter determining the value of the distance relay setting and tested with short circuit at 110%and 180% of the transmission line length shows the distance relay has worked according to theP3B JB regulation No. 211/151/P3B/2010 and distance relay can detect disruption in zone 2with a delay time of 0,815 seconds and detect disruption in zone 3 with a delay time of 1,615seconds.

Fault analysis of solar photovoltaic penetrated distribution systems including overcurrent relays in presence of fluctuations

Since 1988, the system relay engineer of Kansas Power & Light Gas Service has served as a guest lecturer for the course on fault analysis and protection of power systems at Kansas State University. He meets the class five times during the semester. Two of these visits are field trips. In the other three visits he discusses power systems protection from a practicing engineer's point of view. He also discuss a practical design problem prepared for this class. The details of the course, the design project, and other activities are described. The benefits of such cooperation between university and industry are outlined. The main objectives of this course are to: make the students familiar with symmetrical components and fault analysis; make the students familiar with computer methods for fault analysis; make the students familiar with directional overcurrent, differential, distance, and pilot protection; impart practical knowledge on protection to the students; are prepare students for projection-related jobs in the utilities.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Knowledge of accurate zero-sequence line impedance parameters of transmission lines is critical for power system engineers since they play a key role in the settings of distance and directional protection relays, and fault location applications. Double-circuit transmission lines involve zero-sequence mutual impedance due to mutual coupling between the conductors, in addition to the self-impedance. The paper presents an offline estimation technique for zero-sequence self and mutual impedance parameters for double-circuit transmission lines using data from disturbance recorders from both terminals. The most accurate distributed parameter line model is used, and simulation tests prove the accuracy of the algorithm. The application of zero-sequence mutual coupling compensation in distance protection of double-circuit lines using the estimated parameters is also presented.

The transient components are introduced in the extra high voltage (EHV) transmission lines during the faulty conditions. The transients may damage the power system equipments as well as may also lead to the mal-operation of equipments utilized for a specific application in the power network. Analysis of faults in the presence of series compensation in the EHV transmission line may help to design suitable series compensation. This paper addresses the effect of power system faults on the voltage and current waveforms in the presence of series compensation of EHV transmission lines. The detailed simulation study of transmission line faults with and without series compensation has been carried out in MATLAB/Simulink environment. The simulation results show impacts of faults on the system voltages and load currents with and without series compensation of the lines.

With the high penetration of Renewable Energy Sources (RES) in power systems, the short-circuit levels have changed, creating the requirement for altering or upgrading the existing switchgear and protection schemes. In addition, the continuous increase in power (accounting both for generation and demand) has imposed, in some cases, the need for the reinforcement of existing power system assets such as feeders, transformers, and other substation equipment. To overcome these challenges, the development of superconducting devices with fault current limiting capabilities in power system applications has been proposed as a promising solution. This paper presents a power system fault analysis exercise in networks integrating Superconducting Cables (SCs). This studies utilized a validated model of SCs with second generation High Temperature Superconducting tapes (2G HTS tapes) and a parallel-connected copper stabilizer layer. The performance of the SCs during fault conditions has been tested in networks integrating both synchronous and converter-connected generation. During fault conditions, the utilization of the stabilizer layer provides an alternative path for transient fault currents, and therefore reduces heat generation and assists with the protection of the cable. The effect of the quenching phenomenon and the fault current limitation is analyzed from the perspective of both steady state and transient fault analysis. This paper also provides meaningful insights into SCs, with respect to fault current limiting features, and presents the challenges associated with the impact of SCs on power systems protection.

Optimal allocation of fault current limiters for sustaining overcurrent relays coordination in a power system with distributed generation

Technological developments in protective devices have established the basis for appearance of numerical overcurrent relays (OCRs), which enable the users to apply their desired time‐current characteristics (TCCs). This study propounds novel stepwise and combined stepwise–piece‐wise linear TCCs and presents clear procedure to utilise them for coordinating OCRs in large meshed power systems. The TCCs keep constant time interval between the main/backup relay pairs within entire fault current range. They are examined first by coordinating the OCRs in a 4‐bus power system and by coordinating the ground fault OCRs in a practical 60 kV looped power system. Then, the OCRs of the IEEE 14‐bus test system, which is a rather large meshed power system with 39 OCRs and 102 main/backup pairs, are coordinated by using the novel TCCs. The same relays in the aforesaid power systems are coordinated using some non‐standard TCCs recently introduced in the literature. The comparison verifies that the lowest operating times are achieved by using the novel TCCs. The devised TCCs are simply formed as look‐up tables to be exactly set on the existing industrial relays. This fact is verified by setting them on an industrial OCR, and then, by testing the relay through the current injection method.