used in the distribution lines to the level used by the customer. Please download the latest version for the best user experience: Internet Explorer (version 10 or higher), Chrome, Firefox, Safari or Opera. For 66/11 kV substation, following minimum electrical & safety clearances are required. Hand written calculations are hard and laborious often flawed because of all the conversions required. Earth-fault current in the 11kV system could be well over 100kA (peak!) Indoor and Outdoor Termination for 11 kV, 22 kV and 33kV Cables Used in MSEDCL 2.1 Nominal System Voltage : 11kV, 22kV, 33kV 2.2 Voltage variation on supply side : 10 % 2.8 Fault level As a (kV) Break Time (mS) 11kV (incl 6.6kV etc) Demand of power increases day to day. SNTL Prague, Czech Republic, 1970. A : 1000 MVA. >> h. Maximum system fault level at 33 kV & 11kV bus es shall be 26.2kA for 1 sec & 18.3kA for 1 sec respectively. By joining you are opting in to receive e-mail. People confuse your ability to perform with your ability to interview. So they had planned to deliver the desired voltage with 10 % as extra (110%) to match the transmission loss and line drop. 27-36. doi: 10.11648/j.epes.20140302.13 Abstract: The aim of this research work is to carry out fault analysis of 11KV distribution power system . JavaScript is disabled. Hi. INTRODUCTION TO PROTECTIVE RELAYING.pptx, Series & shunt compensation and FACTs Devices, Electrical 132kv substation project .. shakir, Sample calculation-for-differential-relays. For example, the equivalent MVA at branch A (consisting of network feeder, transformer T1 and power line V1) is. Calculation of Three-Phase Balanced Fault Currents - Ebrary In conventional power systems, the system . It's recommended this table is used 5.11 All new substations within 100 metres of an existing 11/6.6 kV ring circuit to which the connection is to be made shall be ringed. Fault level on 11A1 / 11A2 = base MVA/effective impedance upto the bus. Also known as the Impedance Method. Single Phase with Cable Run. We pay respect to Elders past and present. Apply effective risk management The electric power industry will continue to make distribution system reliability and customer-level reliability a top priority. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. To access pad mount and ground substations please contact an Exclusion Zone Officer. Promoting, selling, recruiting, coursework and thesis posting is forbidden. A1-6 Fault level on 11kV side for percentage impedance = 100 x 10 = 97.98MVA Of 10.206 (from A1.5) on 10MVA base 10.20 A1-7 Length of 11 KV overhead line from 66KV sub Station to factory site = 1.5KM A1-8 Size of conductor = Mink A1-9 Resistance of Mink conductor = 0.456 ohnm/KM . Vol. Next, for the 69/12kV X=0.076 p.u. . Click Here to join Eng-Tips and talk with other members! Fault levels on our network are affected by both internal and external factors, such as the Transmission Network Service Providers network, generators and customer connections. For simplicity, resistance will be neglected. [Solved] Two parallel alternators each rated 11 kV 50 MVA - Testbook 66/11 Kv Distribution Substation Design - IJERT Fault Current Calculator The SlideShare family just got bigger. 4 0 obj Finally, the initial symmetrical short-circuit current at the fault point can be calculated from the equivalent network MVA. In order to validate the accuracy of the MVA Method, we will calculate the initial symmetrical short-circuit current at the fault point using the calculation method based on IEC 60909. An advantage of this method is that the short-circuit voltage of the transformer (percentage value of reactance) is given directly in relationship with the nominal apparent power of the transformer. PDF TECHNICAL SPECIFICATION FOR - Maharashtra State Electricity A consumer is supplied at 380V 3 phase from a 11 kV substation through a 1500 kVA 11kV/380V transformer and a 380V cable as shown in Fig. of customer 11-kV main switch shall have an operating time not exceeding the maximum allowable time-current curves for phase fault and earth fault as shown in Drg. This method is used very often but requires knowledge of steady-state conditions before the short-circuit occurrence, which reduces its applicability for general and fast calculations. SelSystemTypeTitle. Single Line Diagram of 11kV Substation - Circuit Globe As you know, interviewing is a staged, contrived event. I'm interested in hearing about how people out there deal with the problem of controllong fault levels in 11kV distribution substations. Its a two step process as follows: Rule of thumb for Brisbane Urban substations at 11kv include: Have a question? Add Transformer to System. Performance & security by Cloudflare. all transformers have set nominal tap (0). We design our electricity network (or distribution system) to meet the maximum fault currents set out in the table below. information about pre-fault steady-state is not required. 1.0 SCOPE. but your probably best asking on an Aussie forum than here. Thanks. Effective impedance on 11X1 = 0.258pu (this needs delta to star conversion and series parallel combination of impedance, in the single line diagram) Fault level on 11X1 = 387.44MVA, 20335 Amps. power system operation and control - iallinfo Weve updated our privacy policy so that we are compliant with changing global privacy regulations and to provide you with insight into the limited ways in which we use your data. endobj In getting the Zs of 22kV External Distribution Network by the IEC 60909 Method, I might have missed where we get the constant C and the value assigned to it as 1.1. Jun 2007 - Nov 20114 years 6 months. EE 423 - Power System Analysis: Faults - J R Lucas - October 2005 5 Example: A 200 MVA, 13.8 kV generator has a reactance of 0.85 p.u. magnetizing currents and losses in the transformer core are neglected. This is usually achieved by opening the circuit breaker connecting two sections of a substation or generating station busbar. The MVA method is an alternative to the earlier mentioned methods. This method is simple, quick, and easy to remember. If the ground resistivity is 800 ohm-meters or more, it will be difficult to obtain the desired low resistance of 1 to 2 ohm for a network station with a single grounding band. jHt-k|iPT 6;' @4Yh >'^B&aJzLAo/TBa;a].)$8Qb73PVHr.D,^{?jy:5jl&FTx_s4aM}S\!5'IJR0]+K_}mVgXc;8oiy>.aGRA1dDIvlakZ5W:lEtcyEQcj7Z;+QZ~ aHgQP[7z 6{+I9b k9ye\b7A4sXi,BWRGpc@0OSnTU`@hj6+VU(d 4sX@+&gY9YmG-CU-*. Please select system type from these two: Three Phase. : Control and stability of power system. Already a member? These can be divided into numerical and numeric-graphical methods. The 132 kV busbar three-phase fault level is equal to 100 MVA/0.0188 pu = 5319 MVA and this corresponds to a three-phase fault current of 5319 MVA/ which exceeds the 21.9 kA rating. calculation of induced voltage in telecommunication lines caused by high-voltage or extra-high-voltage networks. For example, suppose a typical power system where electrical power is generated at 6.6 kV then that 132 kV power is transmitted to terminal substation where it is stepped down to 33 kV and 11 kV levels and this 11 kV level may further step down to 0.4 kv. /Type /Page Avoiding parallel operation of the transformers is probably the least costly approach. security level of the 11kV distribution system. Register today and take advantage of membership benefits. Posted By : / actual instructions in flowcharting are represented in /; Under :nose exercise before and afternose exercise before and after These values also assume an infinite HV bus is applied at the transformer at 1.0p.u. each. 3, No. B : 100 MVA. /F1 6 0 R As more site load is added and extra embedded generation installed, the taps are changed to limit the site fault level. Normally fault level depens on the client requirment. Part 0: Calculation of currents. The system described has a short-circuit duty of approximately 720MVA. If youd like more detailed fault level information, you can complete our online enquiry form. Our short term solution involved two tapped reactors (operating in parallel) to segregate the older 250MVA network from the new 350MVA rated equipment. : In most practical applications, it is not necessary to know the exact time course of short-circuit currents. wn|3h;rmoxw.0~58BB&_*Hx/d~n-*~YP!6V63W_QbPBsUQ;O62G _`c CO,'0Aa Thanks. Muhammad Shahid - Electrical Foreman - LinkedIn As a . 104.248.79.141 Based on the available statistical data, Ekiti State is reported to suffer from severe . Clearly, the bus section and feeder circuit-breakers are all potentially overstressed. Short Circuit Breaking Making Current - Electrical4U New consumer unit required - does it mean none fire rated down lighters need replacing? I need to know the fault current at one of the sites to enable a design of the earthing grid to proceed. Solution: Alternator percentage reactance is based on its own voltage and kVA ratings. We design our electricity network (or distribution system) to meet the maximum fault currents set out in the table below. as above. This website is using a security service to protect itself from online attacks. The equivalent MVA diagram is shown in figure 2. control of propagation and impact of upper harmonics in power system. A Fault Analysis of 11kv Distribution System (A Case Study of Ado Ekiti Electrical Power Distribution District) American Journal of Electrical Power and Energy Systems. Selecting P base as 20 MVA and V base as 11 kV and using the above equations: and the Line-Neutral voltage on the secondary of the transformer is 0.4/3 = 0.230 kV, giving: Three Phase Fault Example Three Phase Fault Example PDF EE 423 Fault Analysis Notes - University of Moratuwa Objective : To be a part of an Organisation where, my knowledge and capabilities can be utilised in a creative way & challenging environment for achieving goals and to upgrade my abilities and skills to grow up in the corporate ladder.<br><br>worked with Siemens PLC S7-400 and also on the WINCC redundancy <br>worked on Constant Current Regulator (CCR) of high voltage of 30 kv, 25 kv, 20 kv, 15 . (11 kV or 6.6 kV in the UK) is typically a complex interconnected ring network containing many substations (indoor, outdoor or pole mounted), while the secondary distribution system (0.4 kV) is generally a radial Joined: 12 January 2012. Standard distribution transformer LV fusing information can be found within the Overhead Construction Manual (PDF 8.0 mb) and the Underground Construction Manual (PDF 21.5 mb). The transformers are delta-star connected with the star point of each 11 kV winding, solidly earthed. /Length 3674 Your browser is out-of-date. The high voltage side protection has not been included in the model as the high voltage protection device had no influence in the study done. By whitelisting SlideShare on your ad-blocker, you are supporting our community of content creators. This website is using a security service to protect itself from online attacks. [3] Kakilli, A.: System Analysis with the MVA Method for Symmetrical Three-Phase Faults. The method consists of the application of special curves that give the value of the a.c. component of the short-circuit current in any moment of the short-circuit fault. At each voltage level the fault level can be ascertained from the reactances given < Prev CONTENTS : Source Next > Fault Levels in a Typical System. 3-phase short-circuit current (Isc) at any point within a LV Why Choose ThinkScan SR2?. Clipping is a handy way to collect important slides you want to go back to later. Prof, PhD, PEPC, IntPE. Recent plans to augment some substations by adding another transformer means that the fault level will go above this (and beyond the CB capacity) unless we take action to limit it. Dostupn na internete: < http://www.jmpangseah.com>. design of grounding systems and the associated determination of allowable touch-voltage,step-voltage andtransferred voltage (for example in the low-voltage grid during earth-fault in the high-voltage grid). 2, A possible guide to maximum 11kV Fault level is that if the 2.5MVA transformer is assumed to be on infinite 66kV bus bars, then the maximum fault level at the substation 11kV bus The aim of this research work is to carry out fault analysis of 11KV distribution power system. These high levels typically require line tripping to remove the fault from the system. Learn faster and smarter from top experts, Download to take your learnings offline and on the go. Impedance (Zk). The determination of the level of short-circuit current at any point of an electrical network can be of interest because of several reasons, e.g. This is in order to account for the system prefault conditions. PDF Fault Level Calculation For Generator - annualreport.psg.fr Fault Level Calculation For Generator . Electric power is an essential facilitator for sustainable development of the modern nation state. 7. The fault currents correspond to a worst-case transformer impedance of 90% of nominal impedance, as transformer standards allow for a 10% tolerance on nominal impedance. One method was previously discussed here and is based on the guidelines presented in IEC 60909. %PDF-1.5 For 1a 00 MVA fault level in a 11kV network, your Thevenin voltage source value will be 11,000/ (sqrt (3) = 6350V (Ph-n) and your series impedance (usually assumed reactance) = j1.21 Ohm.. Voltage (kV) Impulse Voltage (kV Peak) Power Frequency Voltage (kV) 1 0.433 - 3 2 11 75 28 3 33 170 70 11 LOSSES: 11.1 The transformer of HV voltage up to 11kV,the total losses(no-load + load losses at 75 0C) at 50% of rated load and total losses at 100% of rated load shall not exceed the maximum total loss and hence 2, 2014, pp. A 33/11kV indoor GIS substation with a 33kV fault level of 40kA is considered. [1] Jaffari, H.: Fault Current Calculation. Basic short circuit calculation procedure, Protective devices and their coordination in power systems, Electrical substation (one and half breaker scheme), Measurement of hvac (High Voltage Engineering ), 220 KV Substation Operation & Maintenance, 3. Three 15MVA transformers, connected in parallel, are used to step down to an 11 kV busbar from which six 5 MVA, 11 kV motors are supplied. Sometimes, if the system MVA is not available, but its voltage and impedance are given, the short circuit MVA can be calculated by MVASC = KV2 * Y formula.
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