Distance relay pdf

The problem of combining fast fault clearance with selective tripping of plant is a key aim for the protection of power systems. To meet these requirements, high-speed protection systems for transmission and primary distribution circuits that are suitable for use with the automatic reclosure of circuit breakers are under continuous development and are very widely applied. Unlike phase and neutral overcurrent protection, the key advantage of distance protection is that its fault coverage of the protected circuit is virtually independent of source impedance variations.

Distance protection is comparatively simple to apply and it can be fast in operation for faults located along most of a protected circuit.

Impedance Type Distance Relay

It can also provide both primary and remote back-up functions in a single scheme. It can easily be adapted to create a unit protection scheme when applied with a signalling channel. In this form it is eminently suitable for application with high-speed auto- reclosingfor the protection of critical transmission lines. Since the impedance of a transmission line is proportional to its length, for distance measurement it is appropriate to use a relay capable of measuring the impedance of a line up to a predetermined point the reach point.

The basic principle of distance protection involves the division of the voltage at the relaying point by the measured current. The apparent impedance so calculated is compared with the reach point impedance. If the measured impedance is less than the reach point impedance, it is assumed that a fault exists on the line between the relay and the reach point.

The reach point of a relay is the point along the line impedance locus that is intersected by the boundary characteristic of the relay. The loci of power system impedances as seen by the relay during faults, power swings and load variations may be plotted on the same diagram and in this manner the performance of the relay in the presence of system faults and disturbances may be studied.

Distance relay performance is defined in terms of reach accuracy and operating time. Reach accuracy is a comparison of the actual ohmic reach of the relay under practical conditions with the relay setting value in ohms. The impedance measuring techniques employed in particular relay designs also have an impact. It is usual for electromechanical and static distance relays to claim both maximum and minimum operating times.

However, for modern digital or numerical distance relaysthe variation between these is small over a wide range of system operating conditions and fault positions. Traditional distance relays and numerical relays that emulate the impedance elements of traditional relays do not measure absolute impedance.

They compare the measured fault voltage with a replica voltage derived from the fault current and the zone impedance setting to determine whether the fault is within zone or out-of-zone. Distance relay impedance comparators or algorithms which emulate traditional comparators are classified according to their polar characteristics, the number of signal inputs they have, and the method by which signal comparisons are made.

At each stage of distance relay design evolution, the development of impedance operating characteristic shapes and sophistication has been governed by the technology available and the acceptable cost. Since many traditional relays are still in service and since some numerical relays emulate the techniques of the traditional relays, a brief review of impedance comparators is justified. Can you explain the economical and environmental effects or goals of distance protection? Can you explain the topic of Extensive Relay Protection using the microprocessor?

I need this topic as fast as possible …. Thank you. Very useful information. Sir plz tell how can we learn and read switch board drawings. And motor control center. Congratulations for a short presentation of the matter. I suggest including some features I consider important for fully understanding of the distance protection aplications, such as: — tied lines infeed for lines with ties; — arc fault detection; — week infeed; — signaling for pilot applications; — close-up faults; — the use of the reverse zone for busbar fault protection These are what I have in mind at the moment.Metrics details.

The PAZSD methodology employs current coefficients to adjust the zone settings of the relays during infeed situation. Further, the performance of the proposed methodology has been validated in real-time, on a laboratory prototype of Extra High Voltage multi-terminal transmission lines EHV MTL.

Transmission lines are occassionally tapped to provide intermediate connections to loads or reinforce the underlying lower voltage network through a transformer.

Such a configuration is known as multi-terminal transmission lines. For strengthening the power system, MTLs are frequently designed as a temporary and inexpensive measure. However, they can cause problems in the protective system [ 1 ]. As a part of a continuous endeavor to eliminate the problems caused by MTLs and enhance the reliability of the protective system, many protection methodologies have been developed.

A few of them are discussed here. Abe et al. The MTLs have been transformed into two terminal lines to achieve fault location accurately.

Nagasawa et al. Though the algorithms proposed by the authors [ 23 ] performed well, their accuracy may be affected by unbalance in the line parameters when different fault conditions occur. Funbashi et al. It consists of organization agent, coordination agent and executive agent. They exchange the information among themselves regarding trip information.

However, lack of global synchronous measurements acquired from different agents may lead to mal-operation of the relay. Gajic et al. However, the reliability of the algorithm depends on the availability of the current channels. Forford et al. The proposed algorithm can differentiate internal fault, external fault and normal load conditions using electric mid-point EMP.

Arbes [ 8 ] has developed differential line protection scheme for the protection of double lines, tapped lines and short lines. However, the performance of the proposed scheme [ 8 ] depends on the local voltage and current measurements. Al-Fakhri [ 9 ] has proposed differential protection methodology against internal and external faults using asynchronous measurements.Such a relay is described as a distance relay and is designed to operate only for faults occurring between the relay location and the selected reach point, thus giving discrimination for faults that may occur in different line sections.

The apparent impedance so calculated is compared with the reach point impedance. If the measured impedance is less than the reach point impedance, it is assumed that a fault exists on the line between the relay and the reach point. The reach point of a relay is the point along the line impedance locus that is intersected by the boundary characteristic of the relay. The loci of power system impedances as seen by the relay during faults, power swings and load variations may be plotted on the same diagram and in this manner the performance of the relay in the presence of system faults.

Traditional distance relays and numerical relays that emulate the impedance elements of traditional relays do not measure absolute impedance.

They compare the measured fault voltage with a replica voltage derived from the fault current and the zone impedance setting to determine whether the fault is within zone or out-of-zone. Relay measuring elements whose functionality is based on the comparison of two independent quantities are essentially either amplitude or phase comparators. For the impedance elements of a distance relay, the quantities being compared are the voltage and current measured by the relay.

distance relay pdf

There are numerous techniques available for performing the comparison, depending on the technology used. They vary from balanced-beam amplitude comparison and induction cup phase comparison electromagnetic relays, through diode and operational amplifier comparators in static-type distance relays, to digital sequence comparators in digital relays and to algorithms used in numerical relays.

Operation occurs for all impedance values less than the setting, that is, for all points within the circle. The relay characteristic, shown in Figure It is to be noted that A is the relaying point and RAB is the angle by which the fault current lags the relay voltage for a fault on the line AB and RAC is the equivalent leading angle for a fault on line AC.

Vector AB represents the impedance in front of the relay between the relaying point A and the end of line AB. Vector AC represents the impedance of line AC behind the relaying point. This is achieved by the addition of a polarising signal. Mho impedance elements were particularly attractive for economic reasons where electromechanical relay elements were employed.

As a result, they have been widely deployed worldwide for many years and their advantages and imitations are now well understood.

For this reason they are still emulated in the algorithms of some modern numerical relays. This demonstrates that the impedance element is inherently directional and such that it will operate only for faults in the forward direction along line AB.To browse Academia.

Skip to main content. Log In Sign Up. Implementation of Distance Relay for Standalone System.

distance relay pdf

Grd Journals. Relays are utilized to protect electric power systems against trouble and power blackouts as well as to regulate and control the generation and distribution of power. The primary function of the protective relay is to sense the fault in the system, is to protect standalone system from islanding, such that the trip coil of the circuit-breaker is energized and the faulty section of the system is disconnected from the rest of the system.

Keywords- Fault, Distance relay, islanding, arc resistance, reach I. Impedance Relay In an impedance relay, the torque produced by a current element is balance against the torque of voltage element.

REL650 - Line distance protection

The current element produces positive pickup torque. Whereas voltage element produces negative reset torque. In other words, an impedance relay is voltage restrained over current relay.

distance relay pdf

It is used for medium transmission line. Reactance Relay A reactance relay is an over current relay with directional restraint. The induction-cup or double-induction-loop structures are best suited for actuating high-speed relays of this type.

Mho Relay The induction-cylinder or double-induction-loop structures are used in this type of relay. The complete distance relay for transmission-line protection is composed of three high speed mho units. A timing unit, connected in a manner similar to that shown for an impedance-type distance relay. Mho distance relays are used for long transmission lines.

Comparison of the Impedance, Reactance, Mho Relay The comparison of different distance relays is given below All rights reserved by www. Trip Law restrain restrain then trip; else restrain. Impedance relay is not inherently directional but can be made so by using Reactance relay on doesn't have Mho relay incorporates features directional unit with it. This delay directional feature nor can be Directional of reactance relay with an 3.

Effect of Arc 5. Least affected No effect Most affected resistance II. All rights reserved by www. RESULTS The results for the simulation which was carried out on the above system are below Fig 8: Simulation result of voltage for Distribution line during faulty condition Above waveform shows sinusoidal voltage waveform but in the interval of 0. The fig 10 and fig 11 shows the simulation result of output voltage and current for impedance relay on Distribution line and effect of fault resistance on transmission line.

Above voltage and current waveform shows that after the interval of 0. Above figure shows the voltage and current waveform after adding the arc resistance on transmission line the impedance relay will trip after the interval of 0. Related Papers. By Muhammad ilyas. By jayesh Prajapati. By Urvashi Dwivedi. Protecive relaying. By Jorge DG Vasco.MATLAB is used to implement programs of digital distance relaying algorithms and to serve as main software environment.

The technique is an interactive simulation environment for relaying algorithm design and evaluation. The basic principles of a digital distance relay and some related filtering techniques are also described in this paper.

A kV, km transmission line and a MHO type distance relay are selected as examples for fault simulation and relay testing.

Distance Relay

Some simulation results are given. Terms — Digital. Generally speaking, we may make the fault analysis and the test by the simulation software, and according to the actual system requirement, choose the suitable protective relay, but for reliability and security considerations, the massive simulations tests are usually undertaken. This is a quite numerous and diverse job; therefore, having a superior simulated environment is important.

The EMTP [1] Electromagnetic Transient Program is the simulation tool that is used to simulate the electromagnetic transient phe nomenon, and power system faults analysis, and it is one of the most widely used programs in the electric utility since Generally speaking, Protective relay performance has been tested with the waveform signals generated by the non real-time simulator like EMTP. This tool was modelled by using a graphically Object-Oriented environment approach integrated with the digital calculate technology that gives more flexibility to create simulation system; therefore, we can quickly develop a program of protective relay algorithms, and a model of protection relays.

Because they commonly exist in the same environment that involves communication ability, it is very easy to develop a convenient graphical tool for building interactive relay test system.

Some examples and simulation results are also provided in the paper. Digital distance protection is a universal short-circuit protection. This algorithm is used to input signals to DSP by discrete voltage and discrete current to judge whether faults occur or not. However, this method is just a program.

distance relay pdf

MATLAB has the advantage of conducting massive calculation functions and its program can be easily developed. Therefore, it is a very suitable tool of protective relay designs and applications for protection engineers.

In addition, we focus not only on the correction of relay operations, but also on the dynamic characteristics of relay. Theref ore, if we can use graphics to show the variance of impedances trace, then the software of interface will beco me more user-friendly and convenient. MATLAB includes excellent graphics capacity and multi-dimension of graphic function, and can change graphics parameters at the same time.

Therefore, many graphs can be shown on the same window to make comparison with one another. This paper focuses on the model and test of digital distance relay. Therefore, the principles and relating techniques of the distance relay will be discussed first, followed by the description of the distance relay practice by MATLAB. Distance relays are also named impedance relays. They are used to calculate line impedance by measurement of voltages and currents on one single end. For example, for MHO type distance relays, the relays compare the.

They immediately release a trip signal when the impedance value is inside the zone 1 impedance circle of distance relay. For security protection consideration, the confirmation of a fault occurrence will not be made until successive trip signals are released in one season. Different formulas should be adopted when calculating the fault impedance due to different fault types.ABB's website uses cookies.

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Sign up. The type tested variant is delivered equipped and configured with complete protection functionality, and with default parameters for easy handling of the product — from ordering, engineering and commissioning to reliable operation. The series IEDs Intelligent Electronic Device has a number of useful features, such as a significantly reduced number of parameter settings and extended IED HMI functionality, including 15 dynamic three-color indication LEDs per page, on up to three pages, and configurable push-button shortcuts for different actions.

In the series IEDs, most basic parameters are set before delivery from the factory. You only need to set the parameters specific to your application.

This allows you to quickly take your IEDs into operation. The application manual includes setting examples to support your protection engineers. The Relion product family offers a wide range of products for the protection, control, measurement and supervision of power systems.

To ensure interoperable and future-proof solutions, Relion products have been designed to implement the core values of the IEC standard. Submit your inquiry and we will contact you. Quickly find an ABB channel partner. Learn more I agree. Navigate Search Login layouts-flyoutmenu-cart. Search Search now. Login to myABB There was a problem with your request. Rate this page General impression. Positive Negative. Your cart Learn more about shopping on ABB.

REL - Line distance protection. Are you looking for support or purchase information? Contact us. Get to know more. Extensive protection for lines and cables. Designed for IEC REL provides protection of power lines and cables with high sensitivity and low CT requirements.

Measurements and setting of all six zones with several setting groups are realized completely independently from each other to ensure high flexibility.Definition: The relay whose working depends on the distance between the impedance of the faulty section and the position on which relay installed is known as the impedance relay or distance relay.

It is a voltage controlled equipment. The relay measures the impedance of the faulty point, if the impedance is less than the impedance of the relay setting, it gives the tripping command to the circuit breaker for closing their contacts. The impedance relay continuously monitors the line current and voltage flows through the CT and PT respectively. If the ratio of voltage and current is less than the relay starts operating then the relay starts operating. In the normal operating condition, the value of the line voltage is more than the current.

But when the fault occurs on the line the magnitude of the current rises and the voltage becomes less. The line current is inversely proportional to the impedance of the transmission line. Thus, the impedance decreases because of which the impedance relay starts operating.

Transmission Line Protection (21)

The figure below explains the impedance relay in much easier way. The potential transformer supplies the voltage to the transmission line and the current flows because of the current transformer. The current transformer is connected in series with the circuit. Consider the impedance relay is placed on the transmission line for the protection of the line AB. The Z is the impedance of the line in normal operating condition. Let, the fault F1 occur in the line AB. This fault decreases the impedance of the line below the relay setting impedance.

The relay starts operating, and its send the tripping command to the circuit breaker. If the fault reached beyond the protective zone, the contacts of the relay remain unclosed. The voltage and the current operating elements are the two important component of the impedance relay. The current operating element generates the deflecting torque while the voltage storage element generates the restoring torque.


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