Angle difference between a bus at the peninsular grid and a bus at the interconnected system for a single phase to ground fault. For example, if the phase c and ground parameters are selected, a fault to. The residual ground current sensing shown in figure 2 is. The symmetrical component voltagecurrent relationship for this network is found simply, by. More over i am implementing a fault location algorithm and all the values needed are scalars and from simulation i get only vectors. These calculations involve determining the current flowing through circuit elements during abnormal conditions short circuits and earth faults. Understanding ground fault and leakage current protection. Restart simulation and compare waveforms of the two circuits. Ac and dc sources, breakers, transformers, rlc branches and loads, transmission lines. For a single phase toground fault, the three networks are connected in series. Symmetrical fault current calculations to determine the fault current in a large power system. Consider a single linetoground fault from phase a to ground at the general three phase. Post fault voltages and currents from both substation terminals were used as the. Three phase fault analysis on transmission line in matlab.
Understanding ground fault and leakage current protection gfcis the definition of a ground fault circuit interrupter is located in article 100 of the nec and is as follows. The most important feature of matlab is its programming. A phase to ground fault is applied at the middle of line 2. Open the three phase transformer inductance matrix type block menu and change the core type parameter to three single phase cores. Three phase fault analysistransmission line matlab simulink. Fault calculations are one of the most common types of calculation carried out during the design and analysis of electrical systems.
Hi i have a model for double circuit transmission system. It also shows that using three single phase transformers to simulate a ygyg coretype. The system neutral must be carried to the linetoneutral loads, in addition to the ground. The majority of system faults are not threephase faults but fault involving one line to ground or occasionally two line to ground fault. We present single lineto ground, linetoline, and double lineto ground faults in sections 9. Threephase fault mathworks makers of matlab and simulink. Matlab power system simulation of resonant grounding fault. In the beginning of the programming process, input boxes has been.
When the insulation of the system fails at one or more points or a conducting object comes into contact with a live point, a short circuit or a fault occurs. Three phase symmetrical fault occurs in three phase systems where the phase. Implement programmable phase to phase and phase to ground fault breaker system. Any fault impedance is multiplied by 3 and included in this connection, as shown in fig. Another aspect to consider is that, at such high fault currents, not only are the stator windings damaged, but burning of the. Also, since only one phase of the lineto ground fault can experience. A graphical user interface gui was created using gui package inside matlab for the developed model. The following three types of singlephasetoground faults as shown fig. Thus for faulted phase, in case of single line to ground fault, we can write. For a single phase to ground fault, the three networks are connected in series. If the system has single phase loads connected from lineto neutral, then it is a 4wire system.
If there were no any grounded neutral, no fault current would have been flow. Consider a single linetoground fault from phase a to ground at the general threephase. Determine the fault current for the following faults. Fault current ia will be thrice the sequence current ia0ia1ia2, for a single phase to ground fault. The single line diagram of a power system is the network which shows the main connections and arrangement of the system components along with their data such as output rating, voltage, resistance and reactance, etc. Matlab is a programming language developed by mathworks. Fault analysis example switch to the fault data tab, and select fault bus number 3 leave as bus fault, single line to ground click calculate the case will be solved first to make sure the analysis will be valid the fault analysis calculation is a linearized calculation about the operating point. Understanding generator stator ground faults and their. A single phase shortcircuit from a single phase conductor to neutral will produce a lower fault current. The subject of this thesis is the single phase earth fault in medium voltage distribution.
If all voltage, current, and frequency measurements are. The use of the positivesequence bus impedance matrix for three phase fault calculations in section 7. While ground fault protective schemes may be elaborately developed, depending on the ingenuity of the relaying engineer, nearly all schemes in common practice are based on one or more of the methods of ground fault detection discussed in this article. Simulation study of single linetoground faults on rural. In the modeling, single line to ground slg fault was chosen to be the fault type and impedance type distance characteristic was choose to be as the protection scheme. Single line to ground fault analysis electrical concepts. But i am not able to dynamically set the fault distance on one of its line. Typically this system can be used in low voltage systems where single phase loads are not. How to create a model for single line to ground fault for. Single phase ground fault ag what would be the sequence network which satisfies above two equations. Lecture notes eee 360 michigan technological university. Fault calculation methods university of new south wales. A device intended for the protection of personnel that functions to deenergize a circuit or portion thereof within an established period of time when a.
The three phase fault block uses three breaker blocks that can be individually switched on and off to program phase to phase faults, phase toground faults, or a combination of phase to phase and ground faults. Current unbalance is calculated the same way as voltage unbalance. This paper presents an effective algorithm to locate single line to ground slg fault at a transmission line. Check whether the package consists of the folowing files. The delta winding effectively blocks the zero sequence impedance contributed by the source. Simulation study of single lineto ground faults on rural teed distribution lines wanying qiu school of basic sciences, east china jiaotong university, nanchang, p. Three zone protection by using distance relays in simulink.
The paper theoretically analyzes the voltages and currents when a single lineto ground fault occurs. Hence by using matlab simulation in computer, the analysis of. Pdf matlab power system simulation of resonant grounding. Provision is also provided for various types of connections of transformers and grounding of generators. Matlab program for short circuit analysis ee1404 power. A single phase phase a to ground fault is applied between the first two transmission lines. Double phase to ground fault classification and fault distance location of double circuit transmission lines using ann conference paper pdf available august 2009 with 532 reads how we measure. The figure below shows the three types of symmetrical faults occurred due to the short circuit conditions, namely phase or line to ground lg fault, phase to phase ll fault and double line to ground llg fault.
Transient over voltages due to restriking are reduced. Some faults can evolve gradually, for example faults caused by broken pin insulators. Rohitha jayasinghe, manitoba hvdc research centre figure 1 i mflux curve. The need of coordinated ground fault relaying is eliminated. Take line mr for example, by using the least square method of matlab. Here, we need to include the impedance of the neutral cable because the unbalanced fault current will flow in the neutral. In order to apply the fault along the line, this line is simulated in two sections of 100 km. Pdf double phase to ground fault classification and. It started out as a matrix programming language where linear algebra programming was simple. Create a per phase perunit equivalent circuit of the power system using either subtransient reactances if subtransient currents are needed or transient reactances if transient currents are needed. Line toline or double lineto ground fault studies may also be required for protective device coordination requirements. Suppose the phase a is connected to ground at the fault point f as shown in a figure below. Simulation study of single linetoground faults on rural teed.
Were talking about lineto ground faults that may damage equipment. Mathematical calculation and matlab programming of. Pdf in order to handle the situation of power system grounding fault better, this paper built. Single line diagram is the representation of a power system using the simple symbol for each component.
Modeling current transformer ct saturation for detailed protection studies dr. First thing which must be understood at this point, that fault current is completing its path through the grounded neutral. The arc extinction process of the three phase fault block is the same as for the breaker block. Power system fault analysis file exchange matlab central. Notice that during fault the transformer currents of circuit 2 stay unchanged for phases b and c whereas current in phase a falls to zero. It can be run both under interactive sessions and as a batch job. Matlab simulink tutorials for beginners sim power systemsbasics of matlab. How to troubleshoot motors and drives, starting at the inputs. The first ground fault does not require equipment to be shutdown. Single phase earth faults in high impedance grounded networks. Modeling current transformer ct saturation for detailed.
Is it possible to have a higher fault current in line to. See the breaker block for details on the modeling of the singlephase breakers. Nowadays the demand of electricity or power are increases day by day this results to transmits more power by increasing the transmission line capacity from one place to the other place. Teed lines are widely used in rural power networks in china. This tutorial gives you aggressively a gentle introduction of matlab programming. Doing so limits the per phase fault current magnitude for a single phase to ground fault to be no greater than the per phase fault current during a three phase fault. Obtain phase voltage at phase a, b and c from the sequence network formed. The three phase fault block uses three breaker blocks that can be individually switched on and off to program phase to phase faults, phase to ground faults, or a combination of phase to phase and ground faults. Sequence network connections for a single phase to ground fault. However, due to sudden external or internal changes in the system, this condition is disrupted.
It follows the traditional analysis methods using the ybus and zbus methods along with the symmetrical components method. A single lineto ground lg fault is one of the most common faults and experiences show that 7080 percent of the faults that. Introduction to short circuit current calculations. As soon as the fault is detected by the protection relays not simulated here, an opening command is sent to the two line breakers of the faulted phase. What is the only case that makes the single lineto ground fault bigger than the 3 phase short circuit fault. A phase toground fault is applied at the middle of line 2.
Sequence network connections for a single phase toground fault. Phase a y v af y bf cf y y v gf phase c phase b cf v af v bf gf. But during the transmission some faults are occurred in the. Implement programmable phasetophase and phasetoground. This is a package to perform power system fault analysis. The thesis provides steps for developing statcom model in simulink and provides the. First, the basic properties of high impedance grounded networks are. Power transfer on the only 400 kv line in service for a single phase to ground fault occurring on this line with high power transfer from esa to tsp. I a, i b and i c are the current and v a, v b and v c are the voltage across the three phase line a, b and c respectively. According following relations for fault currents in the case of lg and lllg extracted from sequence circuits, by assuming z1z2, if z0 ground fault becomes higher than three phase fault. Here are the different test points in a typical three phase motor drive system figure 1. The threephase fault block implements a threephase circuit breaker where the. Networks are normally radially operated but partially meshed. This is much more numerically complicated than the single phase circuit normally used in balanced three phase circuits.
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