Distance protection calculation formulas and procedures slideshare. Evaluation of rolling sphere method using leader potential. This document gives the model setting calculations, line protection setting guide lines, protection system audit check lists, recommendations for protection system management and some details connected with protection. Lightning stock flushing density number of thunderstorm. Setting of the allowed voltage difference for manual and auto synchronism check. Medium voltage products technical guide protection. All formulas and calculation procedures presented in this course are the. For system trip dependability relay failure coverage provide relay failure protection for all transmission lines and transformers connected to the generators high voltage bus.
Typically, distance relays protect transmission lines from power system faults by using the method of step distance protection. For example, if a lightning rod is set at 12 metres above local earth, then for a striking distance d of 33m the attractive radius ra. European commission joint research centre institute for the protection and security of the citizen contact information george solomos address. As discussed in my earlier post on distance protection philosophy, zone1 setting is kept at 80% of the total impedance of the protected line. Scope this document introduces the application of the distance protection function in the ref 542plus feeder terminal. The calculations are related to fire safety in buildings.
Calculation of distance protection settings in mutually. Unlike phase and neutral overcurrent protection, the key advantage of distance protection is that its fault coverage of the protected circuit. Desigr ers thought that protection was not necessary in many cases because the antenna mast was relatively short 10 meters or less. Scheme communication logic for distance or overcurrent protection zcpsch. Referenced formulas refer to formulas listed in the same document step 1 surface area is 4334 sq. Rolling spheres method for lightning protection epow 6860 surge phenomena fall 2007 joe crispino 1. Example design of a galvanic anode cathodic protection. The fact that it combines both the directional and the.
Distance protection of seriescompensated lines problems and solutions page 4 of 34 q v ref v i p. Rolling sphere method surge impedance r h r v e z h. The numerical distance protection relay used is rel 5112. This includes fundamentals of measuring distance to fault based on electrical signals from one end of the circuit. Calculate whether lightning protection is required or not for following building. Transmission line setting calculations beyond the cookbook.
Calculating the fall clearance for a fall protection. The structural calculations included here are for the analysis and design of primary structural system. For example z is a complex impedance that consists of the resistance r and reactance x, or the magnitude zmag and angle zang, and may be written as. Zone 3 also provides backup protection for adjacent lines sections. Digital and numerical distance protection relays may have up to five or six protection. By parallel calculation and monitoring of all six impedance loops, a high degree of sensitivity and selectivity is. Fall clearance calculation using an srl before fall free fall ffd hs dd sf cr post fall ah. Calculation of idmt over current relay settings 505150n51n calculation model for thermal relay siemens 7sj64. Because the mho relay is affected by arc resistance more than any other type, it is applied to longer lines. Calculation of blast loads for application to structural components report eur 26456 en. These calculations are required for successful implementation of protection of power system and. Article calculation of distance protection settings in.
The following safety and common symbols may be used in this manual and on the equipment. Setting procedures are only discussed in a general nature in the material to follow. So question will come in your smart brain that why 80% even though zone1 is meant for primary protection. Principles and characteristics of distance protection. Distance protection, in its basic form, is a nonunit system of protection offering considerable economic and technical advantages. Ieee 1584 arc flash calculations published by the institute of electrical and electronics engineers and titled guide to performing arc flash calculations, ieee 1584 provides empirical formulas for determining arcing fault current, flash protection boundaries, and incident energy. This document gives the model setting calculations, line protection setting guide lines, protection system audit check lists, recommendations for protection system management and some details connected with protection audit. Equation 7 leads to the wellknown concept of zerosequence. Determine the reach either impedance reach zr or x reach and time delay settings of. Calculate lightning protection for building structure. Bus protection is an application that demands many sets of cts be connected to the relays. He has authored and presented numerous technical papers and. Simulation examples are included to illustrate the need for fault studies in order to.
History of lightning protection system design in tactical sstems many older communication systems do not have lightning protection incorporated into their design. Distance protection is relatively simple to use and it can be quick in service for. Distance protection calculation formulas and procedures 1. The distance protection function is designed to provide selective power system feeder protection. Protection relays differential relays high impedance differential relay highimpedance differential relays are typically used for bus protection.
In this video we have explained calculation for idmt over current relay setting calculation. Figure 1 shows a threezone step distance relaying scheme that provides instantaneous protection over 8090% of the protected line section zone 1 and timedelayed protection over the remainder of the line zone 2 plus backup protection over the adjacent line section. Today, in computerbased relays, the relay equation is directly implemented in the relay. If you continue browsing the site, you agree to the use of cookies on this website.
The following equation 7 is used to calculate the fault impedance in the case of a fault between two specific phases with no ground connection. Transformer protection application guide this guide focuses primarily on application of protective relays for the protection of power transformers, with an emphasis on the most prevalent protection schemes and transformers. When coordinating distance and overcurrent elements, it is common for high probability double contingency cases n. For example, consider the case of a distance function that uses positive sequence voltage as the polarizing signal. Blue items in this example refer to the corresponding items as detailed in the companion document titled design of a galvanic anode cathodic protection system for a pipeline. The attachment of non structural elements is the responsibility of the architect or designer, unless specifically shown otherwise. The flash protection boundary is the distance at which staff without personal protective equipment ppe may suffer seco nddegree injuries that can be cured.
Common reach and time settings for a 3zone distance relay protection are presented in figure 6. Numerical distance protection relay commissioning and. Study of lightning safety distance using rolling sphere method. Calculate no of down conductor for lightning protection area of building structure. Commission and testing with the aims to calculate appropriate settings for the protection relay, configure the relay, install, commission and testing the entire protection. The characteristics for a phase distance function and a ground distance function that use positive sequence voltage polarization are shown in figure 3 1 and are drawn for a phasetophase and phasetoground fault respectively. For example, if the fall clearance of a fall protection system is 6 meters 19,6 ft and the distance from the working platform to the lower level is only 5 meters 16,4 ft, a worker will still hit solid ground when using that fall protection system. Joint research centre, via enrico fermi 2749, tp 480, 21027 ispra va, italy. Calculation of blast loads for application to structural. The second video in our endtoend testing series continues our introduction to transmission line protection also called impedance protection, 21element protection, or line distance protection. Electrical distribution systems must be designed to withstand the maximum expected fault short circuit current until the short circuit current is cleared by a protective device. Fundamental distance protection will contain instantaneous directional zone 1 relay protection and one or more timedelayed zones. Calculation of distance protection settings in mutually coupled transmission lines.
The engineer assumes no responsibility for work not a part of these calculations. Distance protection calculation formulas and procedures. Tutorial on distance and over current protection sample system g 400 kv kolaghat 400 kv jeerat 220 kv jeerat km twin moose 80 km twin moose 200 km twin moose 162 km twin moose 4x315 mva z0. Regulation of protection from emf 3 5 defines two areas that need calculation of emf values. This method uses the line impedance as the basis to form zones of protection and each zone is calculated by a predetermined percentage of the line impendence. Ground distance relays understanding the various methods of residual compensation, setting the. The formulas are valid for systems ranging from 208 v to 15 kv.
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