Distance Protection Relays Research Articles

A Theory of Six-Line Transmission System's Fault Phase Selection Base on Wide Area Measurement System

The parallel transmission lines on the same tower and six-phase transmission system both have the characteristic of narrow corridor, less occupied fertile soil and large transmission capacity, so they have been widely applied and laid great attention. The WAMS provides a new technical means for the safe and stable operation of six-line transmission system. Based on electrical signals of transmission lines gained from WAMS, this paper uses long line equation to calculate fault current, and analyzes the fault current with six sequence components method. On basis of magnitude and angle characteristic of six sequence components, a theory of fault phase selection for six-line transmission system is proposed. Theoretical analysis and EMTDC simulation tests show that this method is not affected by distributed capacitance and transition resistance, and can correctly select the fault phase at any case of operation mode and fault condition. It can provide effective fault phase selection logic for distance relay protection of six-line transmission system.

Distance Protection Settings Based Artificial Neural Network in Presence of TCSR on Electrical Transmission Line

This research paper study the performance of distance relays setting based analytic (AM) and artificial neural network (ANN) method for a 400 kV high voltage transmission line in Eastern Algerian transmission networks at Sonelgaz Group compensated by series Flexible AC Transmission System (FACTS) i.e. Thyristor Controlled Series Reactor (TCSR) connected at midpoint of the electrical transmission line. The facts are used for controlling transmission voltage, power flow, reactive power, and damping of power system oscillations in high power transfer levels. This paper studies the effects of TCSR insertion on the total impedance of a transmission line protected by distance relay and the modified setting zone protection in capacitive and inductive boost mode for three zones. Two different techniques have been investigated in order to prevent circuit breaker nuisance tripping to improve the performances of the distance relay protection.

GECO: Global Event-Driven Co-Simulation Framework for Interconnected Power System and Communication Network

The vision of a smart grid is predicated upon pervasive use of modern digital communication techniques to today's power system. As wide area measurements and control techniques are being developed and deployed for a more resilient power system, the role of communication network is becoming prominent. Power system dynamics gets influenced by the communication delays in the network. Therefore, extensive integration of power system and communication infrastructure mandates that the two systems be studied as a single distributed cyber-physical system. This paper proposes a power system and communication network co-simulation framework (GECO) using a global event-driven mechanism. The accuracy is tunable based on the time-scale requirements of the phenomena being studied. This co-simulation can improve the practical investigation of smart grid and evaluate wide area measurement and control schemes. As a case study, a communication-based backup distance relay protection scheme is co-simulated and validated on this co-simulation framework.

Effects of Shunt FACTS Devices on MHO Distance Protection Setting in 400 kV Transmission Line

This paper presents a study on the performances of distance relays setting in 400 kV in Eastern Algerian transmission networks at Sonelgaz Group (Algerian Company of Electricity) compensated by shunt Flexible AC Transmission System (FACTS). The facts are used for controlling transmission voltage, power flow, reactive power, and damping of power system oscillations in high power transfer levels. The direct impacts of SVC devices i.e. Thyristor Controlled Reactor (TCR) and the Thyristor Switched Capacitors (TSC) insertion, on the total impedance of a transmission line (<i>Z</i><SUB><i>AB</i></SUB>) protected by MHO distance relay are investigated. The modified setting zones protections (<i>Z</i><SUB><i>1</i></SUB>, <i>Z</i><SUB><i>2</i></SUB> and <i>Z</i><SUB><i>3</i></SUB>) have been calculated in order to improve the performances of distance relay protection and prevent circuit breaker nuisance tripping. The simulation results are performed in MATLAB software and show the direct impact of the thyristors firing angle (<i>α</i>) on the total impedance of the protected line.

Impact of SVC on the protection of transmission lines

The impact of Static Var Compensator (SVC) on the apparent impedance seen by the transmission line distance relay is investigated in this paper. Analytical results are presented and verified by detailed simulations. It is shown that the connection type of the windings of the shunt coupling transformer of the SVC has a remarkable effect on the apparent impedance seen by the distance relay. Six different phase to phase and phase to ground measuring units of the distance relay are simulated to resemble the behavior of the relay. The impact of SVC is more pronounced on the apparent impedance seen by the phase to ground fault measuring units than the others as is shown by the results. Simulation results include different power system operating conditions, SVC control system settings and different fault-type scenarios. The impact of SVC on the relay tripping boundaries is also clearly demonstrated. Detailed and sophisticated models are used for simulating distance protective relay in a digital simulation environment.

The Research of Relationship between SICSFCL and Distance Relay Protection of Power Grid

A Saturated Iron Core Superconducting Fault Current Limiter (SICSFCL) provides a powerful fault current limitation in high voltage and high capacity power grid. A 35kV/90MVA SICSFCL was installed in a 35 kV network for live-grid operation, in January 2008 at Puji substation, Kunming, China. With deep research on SICSFCL, the matching problem between SICSFCL and relay protection currently needs to be solved. This paper analyzes the influence that SICSFCL brings to the distance relay protection which is used widely in high voltage power grid, and considering the characteristics of microcomputer-based protection, this paper proposes a new algorithm to eliminate the influence.

Rough-Set-based timing characteristic analyses of distance protective relay

Nowadays protection engineers are suffering from very complex implementations of protection system analysis due to massive quantities of inconsistent data, let alone coming from diverse intelligent electronic devices (IEDs). Thus, a novel Rough-Set-based data mining strategy has been formulated to resolve the inconsistency in a distance protective relay's decision system (i.e. a transformed relay event report) in such a way that the relay's timing characteristics hidden in its decision algorithm of protection operations have been successfully discovered. Using Rough Set Theory, the inherent uncertainty and vagueness in the relay event report have been resolved using the concepts of discernibility, elementary sets and set approximations. The timing characteristics that have been successfully discovered are in relation to the relay trip assertion activity, impedance element activation, fault characteristics, circuit breaker operation and its overall decision system approximation.

Advanced distance protection technique based on multiple classified ANFIS considering different loading conditions for long transmission lines in EPS

The advanced application of artificial intelligent techniques (AIT) was introduced recently in protection of transmission lines in electric power systems (EPS). Adaptive neuro-fuzzy inference system (ANFIS) is a promising tool among these AIT. In this proposed research, the application of ANFIS for distance relay protection for long transmission line, under different loading conditions, in electrical power systems (EPS) will be introduced and discussed. Based on multiple classified ANFIS and considering different loading conditions for long transmission lines in EPS, the suggested and proposed technique deals with fault detection, classification, and location in long transmission lines. All these tasks will be addressed in details in this article. It considers, firstly, detecting the fault occurrence in very short time and isolate the faulty section of the long transmission lines. Secondly to classify the fault type and deduce which of the three phases are exposed to the fault. Finally, locating the fault will be achieved easily even if the procedure here is completely different from short and medium transmission lines. The input training data of the ANFIS detection units are firstly derived from the fundamental values of the voltage and current measurements [using digital signal processing via discrete Fourier transform (DFT)]. These measurements were simulated considering different loading conditions.

An accurate technique for locating faults by distance relays

This paper presents a new protection scheme for improving the performance of the distance protective relays in transmission systems. The determination of fault zone by the proposed scheme is based on data sheared locally with other distance relays at the same station, in addition to a command from the distance relay on the other end of the protected line. Based on analyzing this information the relay decides the correct fault zone. With the proposed scheme, the first zone in the distance relay covers the full length of the protected line while the second zone covers the full length of any line following the protected line irrespective of its length, etc. The scheme is examined against wide range of setting problems of a real part of a HV network with real relay settings. It succeeds in solving distance relay setting problems, e.g. the problem of a long line following a short line or vice versa, low in-feed, open CB at one end and high impedance faults.

Effects of a voltage compensation type active superconducting fault current limiter on distance relay protection

On the basis of a voltage compensation type active superconducting fault current limiter (SFCL) proposed in previous work, the effects of this type SFCL on distance relay protection are studied in this paper. Under the condition that the active SFCL is placed behind the relay element, its current-limiting impedance will be added into the measured impedance between the relay and the fault points. As a result, in order to prevent the refused operation of the relay, the measured impedance should be revised. According to the three different operation modes of the active SFCL, we present the corresponding three modified formulas. Furthermore, using MATLAB, the model of the dual-source power system with the active SFCL is built, and the impacts of the active SFCL on the distance relay protection are studied in detail under the different current-limiting modes and fault distances. The simulation results show that: without using the modified formulas, the introduction of the active SFCL will reduce the protection distance of the relay, and in the case that the modified formulas are adopted, the three modes of the active SFCL will not affect the measured impedance of the relay, and further the validities of the proposed modified formulas can be testified.

Modeling and Simulation of Out of Step Blocking Relay for Power Swing using Concentric Polygons Scheme

This paper investigates a power swing effect on a distance protection relay performance installed on (HV/EHV) transmission line as well as power system stability. A conventional distance relay can’t properly operate under transient stability conditions; therefore, it cause mol-operation, and it will adversely impact on its trip signals. To overcome this problem, the Out Of Step (OOS) relay has modeled and simulated to joint with distance relay to supervise and control on its trip signals response. The setting characteristics technique of the OOS based on concentric polygons scheme method to detect power swing under transient stability situation. This study ia a modeling and simulating using (Maltab\ Simulink) software. A Two relays had been performed and tested with two equivalents network connected to ends. The results of this study showed an activity and reliability of this way to control the distance relay response under a transient stability conditions and it indicated the possibility to find out faults which may occur at period of power swing.

Modeling and Simulation of Out of Step Blocking Relay for

This paper investigates a power swing effect on a distance protection relay performance installed on (HV/EHV) transmission line as well as power system stability. A conventional distance relay can’t properly operate under transient stability conditions; therefore, it cause mol-operation, and it will adversely impact on its trip signals. To overcome this problem, the Out Of Step (OOS) relay has modeled and simulated to joint with distance relay to supervise and control on its trip signals response. The setting characteristics technique of the OOS based on concentric polygons scheme method to detect power swing under transient stability situation. This study ia a modeling and simulating using ( Maltab\ Simulink ) software. A Two relays had been performed and tested with two equivalents network connected to ends. The results of this study showed an activity and reliability of this way to control the distance relay response under a transient stability conditions and it indicated the possibility to find out faults which may occur at period of power swing

Analysis of overload conditions in distance relay under severe system contingencies

Distance relay protection is widely used worldwide for protection scheme on high voltage transmission lines. This protection tends to be prone to load encroachment condition causing possible undesired tripping condition. Investigations of two system disturbances that occurred in TNB’s (Tenaga Nasional Berhad) Grid in the year 2003 and 2005 have clearly revealed the occurrence of load encroachment condition following line overloads after large number of line tripping. Examination of the impedance locus trajectory during the overload events have enabled a distinction be made between power swing and load encroachment phenomena. This paper presents the analysis and findings of the investigation of the load encroachment phenomena of the two events, including other related transmission line contingencies.

A Distance Protection Relay for a 1000-kV UHV Transmission Line

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A traditional distance protection relay uses a lumped parameter model of the transmission line. For a long 1000-kV UHV line with large distributed capacitance, such a simplified line model is inadequate and can cause malfunction of the relay due to large errors in the impedance measurement. This paper presents a new line model for a distance relay and the procedure of reliable fault impedance measurement and relay setting. It describes the proposed application of the relay developed to a 645-km 1000-kV UHV transmission line including shunt reactor compensation, which is currently being constructed in China. Tests are carried out on an RTDS (real time dynamic system) to evaluate the relay performance, showing significant improvement compared to a more traditional distance relay. The new distance relay is shown to satisfy the requirement of 1000-kV UHV transmission line protection. </para>

A New Weak Fault Component Reactance Distance Relay Based on Voltage Amplitude Comparison

A new weak fault component reactance distance relay is proposed in this paper. By adaptive setting of the compensated voltage, the scheme synthesizes the performance of the impedance distance relay and the reactance distance relay. The distance protection relay on the receiving end will misoperate when the fault resistance is larger than the critical resistance. So a new switching criterion is applied to eliminate this disadvantage. Based on that, the proposed scheme can detect the fault with the high fault resistance in the setting coverage, regardless of whether the relay is located at the receiving end or the sending end. Test results from the simulation and experimental conditions show that the new scheme is successful in detecting the internal fault. It has higher sensitivity and selectivity during different conditions than the traditional fault component protection schemes.

Postfault Analysis of Operation of Distance Protective Relays of Power Transmission Lines

This paper deals with the postfault analysis of the operation of distance protective relays from the line terminals. The signals of the digital distance relays are processed in the offline regime with the aim of evaluating the particular relay operation case. First, the program enables imitating the fault-loop impedance measurements of the distance relays. Second, the two-end unsynchronized measurements of the relays are considered. The unknown synchronization angle is determined by using the developed noniterative procedure. Then, the distance to fault is calculated. It is applied for calculating the actual values of impedance for the line sections. Comparing the results of these two ways performs analysis of operation of the relays under resistive fault cases. The described postfault analysis algorithm has been tested with the fault data obtained from versatile Alternative Transients Program-Electromagnetic Transients Program simulations. The examples are reported and discussed

Performance Evaluation of a Distance Relay as Applied to a Transmission System With UPFC

This paper presents analytical and simulation results of the application of distance relays for the protection of transmission systems employing flexible alternating current transmission controllers such as the unified power flow controller (UPFC). Firstly a detailed model of the UPFC and its control is proposed and then it is integrated into the transmission system for the purposes of accurately simulating the fault transients. An apparent impedance calculation procedure for a transmission line with UPFC based on the power frequency sequence component is then investigated. The simulation results show the impact of UPFC on the performance of a distance protection relay for different fault conditions; the studies also include the influence of the setting of UPFC control parameters and the operational mode of UPFC.

A Novel Algorithm to Determine Minimum Break Point Set for Optimum Cooperation of Directional Protection Relays in Multiloop Networks

Determining minimum break point set (MBPS) is necessary before setting distance protection relays or zero-sequence protection relays in multiloop extremely high voltage power networks. Determining directional simple loops (DSLs) and relative sequence groups (RSGs) is the prerequisite of traditional algorithms which are used to determine MBPS. In order to reduce the CPU time and complexity of calculating MBPS, a new concept named as protection relay dependency dimension (PRDD) is presented for the first time in this paper. By comparison of PRDD in a multiloop network, the MBPS can be determined, and the process of comparisons will not stop until the MBPS of the multiloop networks is discovered. In the meantime, the RSG could be easily determined by means of judging whether the primary protection relay set of a protection relay is null or not. The new algorithm leaves out those laborious steps, such as determining all of the DSLs and RSGs. Some examples are given to illuminate the novel algorithm presented in the paper to be simple and effective.

Performance of Distance Relays on Shunt—FACTS Compensated Transmission Lines

This paper presents a study of the performance of distance protection relays when applied to protect shunt Flexible AC Transmission System (FACTS) compensated transmission lines. The objective of this study is to evaluate the performance of distance relays on transmission lines with FACTS devices applied for mid point voltage control. Effect of two types of shunt FACTS devices, Static Var Compensators (SVC) and Static Synchronous Compensators (STATCOM) are studied. The study is conducted in three stages. First the situation is studied analytically, where the errors introduced in the impedance measurement due to the presence of shunt FACTS devices on the line are analyzed. In the second stage, the situation is simulated using transient simulation software, EMTDC. In this method, the response of FACTS devices for different fault conditions and system conditions is also modeled. This method brings out some unique problems that would be experienced by the distance relays due to some specific characteristics of the FACTS devices. Finally, the findings are confirmed by testing a commercial distance relay using a Real Time Digital Simulator (RTDS). The results obtained by testing the commercial relay validate the analytical and simulation studies.

A Study on the Effects of New Facts Installations on Existing Distance Protection Relays

The UPFC, which is one of the many FACTS devices that are in use in the modem power system, is able to independently control the active and reactive power in the transmission systems by injecting a controlled voltage in series. The series injected voltage by the UPFC can be perceived as a change in transmission line impedance by existing distance protection relays and affect their correct operation. This paper first uses EMTDC models of the UPFC and surrounding power system of the Kangjin substation located in Jeonla-namdo province in Korea to investigate the impedance variation according to different UPFC operating conditions under steady and transient states. Then the operation of the UPFC protection controls, and impedance variations seen by the distance protection relay were reviewed under fault conditions to investigate the possibility of relay misoperation, and the need for relay protection setting modifications.