Main Substation Research Articles

High Temperature Superconductivity Application Readiness Map - Energy Delivery - Transmission, Substation and Distribution

The International Energy Agency's High Temperature Superconductivity Technology Collaboration Program (IEA HTS TCP) analyzed energy delivery applications for HTS. The product was a Readiness Map that illustrates the Technology Readiness Levels (TRL) over time of HTS applications. Assessing these TRL levels is important since the electric power system that supplies our residential, commercial and industrial sectors is experiencing a transition to safer, more efficient and cleaner power supply. The international experts assessed the present degree of technological development of the main transmission, substation and distribution HTS applications in the energy delivery sector and estimated the pathway to commercialization phase. Instead of using a specific TRL number 1-9 for each of the applications, they are categorized into low, medium and high TRL levels. Superconducting fault current limiters and medium voltage AC cables to interconnect substations at the low side of the transformer are currently at a high TRL as they can be purchased in the market. High voltage AC and DC cables are at a medium TRL and could reach a high level TRL level in 2030-2035. Superconducting transformers are at a low TRL and they could reach a high TRL level by 2030-2035.

Sistem Koordinasi Rele Jarak Untuk Pengaman Utama Dengan Rele Arus Lebih Pada Saluran Udara Tegangan Tinggi Di Wilayah Buduran

The transmission system plays an important role in maintaining the continuity of the distribution of electrical energy from one region to another. Disturbances in transmission lines are caused by short circuits, overloads, lightning surges, natural disturbances and others. For this reason, a protection system is needed that is reliable and can identify disturbances quickly while protecting the disturbed part of the system from other parts that can still operate normally. However, the protection system can experience operational failure due to various factors, therefore, apart from the main protection, backup protection is needed which can work when the main protection fails to work. Distance relays can be used as primary protection as well as remote backup protection on high voltage overhead lines. Meanwhile, the overcurrent relay is used as local backup protection if the distance relay fails to work. In this paper, a protection system is designed for the Buduran Main Substation channel using a combination of distance relays as main protection and overcurrent relays as backup protection using simulation method the Digsilent Power Factory. The overcurrent relay will trip at 0.5 and 0.15 seconds. From the Load Flow results, the value is obtained = 3,615 kA, = 4,67 kA and The range impedance according to the conductor cable data at the Buduran region 0,9676, Zone1 1 0,79Ω; 80%, Zone2 1,19Ω; 120% dan Zone3 as 1,48Ω is 150%. Thus the research can be declared successful in carrying out overcurrent protection

Grounding System Design of the main Electrical Substation of stones and minerals breaker plant in Campeche State to comply with the NOM-001- SEDE-2012, IEEE-Std-80-2000, and the Código de Red

This article proposes the design of a grounding mesh for the main electrical substation of 150 kVA in the Breaker Plant in order to obtain a good path to drain overcurrents due to faults and prevent electrical installations from being a danger to connected equipment and users who use electrical installations, allowing voltage control to reduce the risk of shock to people who may come into contact with energized conductors; complying with current regulations NOM001-SEDE-2012, IEEE-Std-80-2000 and the Código de Red and does not represent a danger of failure for the electrical network supplying CFE. There is a grounding system based on a delta of electrodes already many years after its installation and without maintenance and ineffective that has allowed the passage of overcurrents that have damaged motors. It is intended that the new design of the grounding system be reliable and safe and that, in addition, when an electrical installation verification unit (UVIE) arrives, it provides the Load Center with the Electrical Installation Verification Opinion, signing in agreement that it is complying with the applicable provisions of NOM-001-SEDE-2012, Electrical Installations (use), based on IEEE-Std-80-2000.

Повышение качества электроэнергии в системах электроснабжения прокатных станов с использованием преобразователей частоты с активными выпрямителями за счет применения специализированных пассивных фильтров

In recent years, the frequency converters (FC) with active rectifiers (AR) have become widespread due to their advantages. The advantages are the possibility of energy recovery in braking modes of electric drive and support of the set value of power factor at the input of AR. At the same time these converters have a significant disadvantage, that is the deterioration of voltage quality in the in-plant 6–35 kV power distribution network due to the imposition of high-frequency harmonics of the input voltage and current of AR on the resonant area of the supply network frequency response. This disadvantage can be eliminated by using special passive filters in the in-plant power networks. They ensure the shift of the main resonance of currents to a zone free from high-frequency harmonics of the FC with AR. It makes possible to reduce the harmonic distortion coefficient in the voltage sections of the main stepdown substation (MSS) of the enterprise. Processing of experimental data is carried out in the Matlab mathematical package with the Simulink application. Using income data of functioning metallurgical complex CherMK of PJSC “Severstal”, the authors carried out the analysis of voltage quality of 10 kV network using specialized passive filters and without them. The article presents the results of the study of the effectiveness of the use of specialized passive filters in the in-plant power supply system of the rolling complex operating at the CherMK of PJSC “Severstal”. The reasons of the deterioration of the voltage quality in the 10 kV distribution network are studied, and as a result, operational breakdown of the modes of sensitive electrical receivers. A complex mathematical model of the 10 kV network has been developed to study the way to improve the harmonic composition of voltage due to installation of specialized passive filters. This filter allows you to adjust the frequency characteristics of the 10 kV network, shift it to an area free of high-frequency harmonics generated by modern frequency converters with active rectifiers. Thus, the resonance of currents and voltages in 10 kV sections is eliminated. As a result, a significant improvement in the shape of the line voltage and a decrease in the harmonic distortion coefficient of voltage THDU = 75,2–91,2 % to values THDU = 0,49–1,4 % is observed. The main result of the research is the recommendation to use a specialized passive filter to eliminate the negative impact of the harmonic component of the current resonance. The research results can be used to design power supply systems of metallurgical enterprises that have powerful electric drives with active rectifiers.

Power supply reactive power factor control as a function of consumer power and losses in transformers

The system of automatic control of the reactive power factor of the enterprise's power supply system is considered, in which one part of the transformer substations is equipped with adjustable capacitor units, and the second is not. Its advantage in comparison with the power factor control system is shown, firstly, lower requirements for its error and, secondly, the calculation of the consumer with the supplier for electricity is made taking into account the ratio of reactive energy to active energy. An estimate of the error of regulation of the reactive power factor on the higher voltage side of the transformers of the main step-down substation, where settlement meters are installed, is given, with stabilization of the reactive power factor on the low voltage side of these transformers. The synthesis of the system of automatic control of the reactive power factor, built as a function of the power of consumers and power losses in transformers, and the estimation of its error are considered. The proposed control system is intended for power supply systems with a combined load, the use of which will allow the consumer to avoid penalty coefficients to the tariff for active electricity, and ultimately reduce losses in the transmission of electricity and increase the transmission capacity of the electrical network.

Control of a battery energy storage system to compensate for ADN equivalents inaccuracies

This paper proposes a new application for a Battery Energy Storage System (BESS) connected at the main substation of a distribution grid. It consists of controlling the BESS in such a way that the net active and reactive powers entering the distribution network matches as closely as possible the response of a dynamic equivalent model of the latter, used in large-disturbance dynamic simulations of the transmission system. Thus, the BESS compensates for the inevitable inaccuracies of the equivalent, which can be used with higher guarantee of accuracy. Its active and reactive powers are controlled without resorting to any model of that grid. Simulations results are reported on the CIGRE MV test system. Good performances are found in response to disturbances of various severities. The proposed approach would lead to a new service for the BESS, in addition to other purposes for which it has been installed. • A BESS connected at the main substation of a distribution grid can be controlled in such a way that the response of the distribution grid to large disturbances is approaching the response of an equivalent. The latter is a reduced-order model, used in simulations of the transmission system. The overall objective is to compensate for inevitable inaccuracies of that model, and, hence, increase the reliability of those simulations. • The control of the BESS involves the measurement of the voltage phasor at the main substation of the distribution grid. That measurement is used to simulate in real-time the active and reactive power responses of the equivalent. • PI controllers are used to adjust the active and reactive powers produced by the battery and bring the closest to zero the difference between the simulated active and reactive power responses of the equivalent and those of the distribution grid (measured at the main substation). • By compensating the inaccuracies of the equivalent, the proposed control allows less frequent updates of the latter. • The active and reactive power responses of the battery can also be used as an indicator of the accuracy of the equivalent. Indeed, the less the battery is requested to vary its active and reactive power outputs in the event of a large disturbance, the better is the accuracy of the equivalent.

Urban Rail Substation Parameter Optimization by Energy Audit and Modified Salp Swarm Algorithm

Auditing the energy consumption in urban rail is vital for energy consumption evaluation and system parameter design. There are multiple ways to audit energy consumption, but a universal and global approach is missing. The system-level traction energy consumption (STEC) is proposed. Compared to the main substation energy consumption (MSEC), STEC is more accurate by eliminating the influence of step-down loads based on field test studies. An optimization parameter designing model is built, which takes the system cost as the optimal object considering the life span of energy feedback system (EFS)s. The modified salp swarm algorithm (MSSA) is proposed as the optimization algorithm. The numerical tests show that MSSA has better converge performance than salp swarm algorithm (SSA) and particle swarm optimization (PSO). The impact factors of STEC are analyzed. Compared with SSA and PSO, the initial value of the MSSA is improved and it evolves faster. Compared with the case that does not take the no-load voltage of rectifiers and start voltage of EFSs as optimal parameters, the composite cost of the case that takes the abovementioned parameters as optimal parameters is 3.49% less. Compared to the system without EFSs, the optimal system with EFSs can save costs by 29.47%.

High Voltage DC Auto-Transformer Traction Power Supply for Braking Energy Utilization, Rail Potential, and Stray Current Mitigation

For urban rail transit, high-voltage ac power is generally transmitted from the main substation to the traction substation (TS), which employs isolated diode–rectifiers to feed the dc traction power supply system. The train current feeds back to the negative cubicle of TS through the running rail, which is not totally isolated from the Earth. However, the traditional traction power supply (TTPS) shows limitations on braking energy-wasting, high rail potential, stray current, and so on. Thus, a high-voltage dc autotransformer (DCAT) traction power supply (HDATPS) is proposed in this article. Both configurations and principles of three typical HDATPSs are analyzed, which mainly consists of the dc main substation, the dc TS, and the DCAT substation. Then, through modeling of HDATPS and TTPS, the comparisons on braking energy utilization, rail potential, and stray current mitigation are discussed in detail. Finally, the simulation model and experimental platform of HDATPS are built, respectively, and the theoretical analysis is verified with the simulation and experimental results.

Controlled electric vehicle charging for reverse power flow correction in the distribution network with high photovoltaic penetration: case of an expanded IEEE 13 node test network

Over the past years, the penetration of photovoltaic (PV) systems into the distribution network has experienced significant augmentation as the pressure to reduce greenhouse gas emissions into the atmosphere keeps increasing while the prices of the solar components keep reducing. Despite the benefits PV systems bring to the distribution network, the high penetration of this technology into the distribution network could lead to reverse power flow (RPF) when the PV systems produce more than the local loads require. This RPF could result in the malfunctioning of protective devices and their coordination. This research addresses this problem by utilizing electric vehicles (EVs) that are currently revolutionizing the transport sector. Here, the charging of EVs during the day is intelligently controlled to mitigate RPF as a result of the excess power produced by the PV systems. Resolving RPF is achieved through a control system that measures the power flow on each phase of the main grid substation. If at any instance negative power is detected (reverse power), quantified EVs needing recharge are instantly incorporated into the network for charging through the automatic closure of the power switches of the required number of charging points with EVs whose total power demand equals the amount of reverse power detected. The excess power is hence absorbed and stored by the EVs. The proposed method is tested on an expanded IEEE 13 node test feeder and simulated using ETAP software. Simulation results show the effectiveness of the proposed method in eliminating RPF which occurs from 10:00 am to 12:00 noon by connecting the required number of EVs during that timeframe. The proposed method involves the distribution network operators working in synergy with the transport sector to effectively solve the problem of RPF in the distribution network.

Allocation of HV/MV Substations in Iraqi Power Grid Using Delaunay Triangulation

In provincial areas, allocation of the HV/MV substations aims to assign a proper set of numbers and locations of substations to supply loads spatially distributed over a large geographic area with continually emerging towns. This requires identifying the sparse load centers, the existing substations, and the new substations required to cover the potential extension. This paper proposes a method to allocate the main substations to the targeted area based on the lines’ length which are assigned by Delaunay triangulation and geographical coordinates. The proposed configuration is identified by a criterion that is tailored to the Iraqi sub-transmission system in which the standard distances among the substation follow specific patterns. The standard distances that are identified by the proposed methods are represented by the edges of Delaunay triangles. This paper aims to improve the voltage regulation of the distribution grid and avoid problems of overloaded feeders by assigning the proposed locations that reduce the lines’ lengths. The proposed method is verified using simulation tests on Diyala 9-bus system which is a part of the Iraqi 132 kV power system. The results show that the proposed configuration of the substations is reasonably valid and quite close to the real locations of the towns of the system with efficient lengths for the lines.

Research on Fault Detection Algorithm of Electrical Equipment Based on Neural Network

With the rapid development of China’s electrical industry, the safe operation of electrical facilities is very important for social stability and people’s property safety. The failure detection method of conventional electrical equipment is hand detection, which has high experience of the detection person, lacks detection and error detection, and the detection efficiency is low. With the development of artificial intelligence technology, computer-assisted substation inspection is now possible, and substation inspection using an intelligent inspection robot equipped with an infrared device is one of the main substation inspection methods. In this paper, experiments are carried out using several neural network models. For example, if a faster region convolutional neural networks (RCNN) infrared detection model is employed, a good vg16 in the feature region of the extracted image takes into account the quality of the infrared image and the presence of multiple devices. Infrared images can be used to determine the basic features of various electronic devices. In order to detect targets in infrared images of electrical equipment, the fast RCNN target detection algorithm is used, and the overall recognition accuracy reaches 83.1%, and a good application effect is obtained.

Overarching Preventive Sympathetic Tripping Approach in Active Distribution Networks Without Telecommunication Platforms and Additional Protective Devices

Nowadays, distributed generation (DG) has made it possible to generate electricity close to the consumption site, resulting in improved efficiency, less environmental pollution, and higher economic profit. These advantages have led to increased penetration of DGs in the distribution system. Protective devices in a distribution system are set by considering the main substation as the only source for feeding short circuit current. However, with the increased influence of DGs as the second main source of short circuit current in distribution systems the short circuit level changes, which leads to false tripping of protective devices, including overcurrent relays. A sympathetic trip, occurring due to a fault in the adjacent feeder, is one of the most serious challenges. This paper analyzes the sympathetic trip in the presence of synchronous based DGs. The equations related to the participation of DGs and upstream network in feeding the short circuit current are obtained. The effect of different parameters on the probability of occurrence of a sympathetic trip is also investigated. Moreover, a novel fast solution is presented for overcoming the sympathetic trip of synchronous based DGs. The proposed method is introduced using the positive-sequence currents of the DGs and main substation. The sympathetic trip is predicted by adopting this prediction index and its occurrence is avoided. The proposed methodology is independent of telecommunication platforms and additional protective devices and can be applied to various short circuits. The method is tested on a network by simulating in DIgSILENT PowerFactory software. Simulation results show the effectiveness of the proposed methodology in predicting and preventing sympathetic trips.

A control-oriented scalable model for demand side management in district heating aggregated communities

District heating networks have become widespread due to their ability to distribute thermal energy efficiently, which leads to reduced carbon emissions and improved air quality. Additional benefits can derive from novel demand side management strategies, which can efficiently balance demand and supply. However, their implementation requires detailed knowledge of heating network characteristics, which vary remarkably depending on urban layout and system amplitude. Moreover, extensive data about the energy distribution and thermal capacity of different areas are seldom available. For this purpose, the present work proposes a novel procedure to develop a fast scale-free model of large-scale district heating networks for system optimization and control. Each network community is represented and modeled as an aggregated region. Its physics-based model is identified starting from a limited amount of data available at the main substations and includes heat capacity and heat loss coefficients. The procedure is demonstrated and validated on the network of Västerås, Sweden, showing results that are in agreement with data from the literature. Thus, the model is well suited for real-time optimization and predictive control. In particular, the possibility to easily estimate the heat storage potential of network communities allows demand side management solutions to be applied in several conditions.

Automated metering and power quality systems in power supply systems

The article shows that the data of the collected by the automated commercial electricity metering systems are an ensemble of daily realizations of random processes of power consumption of the power supply system. The main purpose of using automated systems of commercial and technical electricity metering is to reduce power consumption. But it is noted that the efficiency of using data of the automated commercial electricity metering system, efficiency and proper management of energy consumption depends on the operators of automated workstations. Considering the rapid improvement of both technical means and mathematical methods that can be applied to address energy efficiency issues, there is a need to transform remote data collection systems from electricity meters, taking into account quality, into a measuring and information structure capable of not only collecting data from meters, electrical energy, but also analyse them. The main method for detecting undercounts is given - the balance method. On the basis of the balance method, it is proposed to automatically calculate the unbalance for each section of the 6, 10 or 110 kV line of the main step-down substations and distribution points, taking into account the number and accuracy classes of commercial metering and technical metering devices. It is proposed to balance the load on the results of calculations performed by automated commercial electricity metering system in order to reduce energy losses and reduce payment for electricity. It is proposed in the work that the automated commercial electricity metering system should calculate the coefficients of form, maximum, load, as well as other morphometric characteristics of the graphs of electrical loads. The work drew attention to a number of problems arising in the calculation of these parameters: electronic meters measure the data necessary for calculations but not with the specified discreteness and, most importantly, their measurement of these parameters of the quality of electrical energy is not metrologically certified, therefore, such data can only be relied on as background information.

Automatic control system of the reactive power factor of the power supply system of the industrial enterprise

Considered is the control of the reactive power factor of the power supply system of an industrial enterprise, which includes: electrical receivers with asynchronous load; workshop transformer substations with and without regulated capacitor units, as well as the main step-down substation with synchronous motors powered from it. It is proposed to consider electrical receivers with capacitor units and a transformer substation as an object of reactive power factor control, on the basis of which the corresponding automatic control system (ACS) is built. An ACS with an algorithm formed as a function of active and reactive power of electrical receivers is considered. The ACS was developed by the reactive power factor of the power supply system of the entire enterprise with shop combined loads. A method is given for calculating the capacity of capacitor units of shop substations. The use of this control system will allow meeting the regulatory requirements for ensuring the limiting values of the reactive power coefficients and thereby reducing losses during the transportation of electricity and increasing the throughput of the electrical network.

Application of State Estimation in Distribution Systems with Embedded Microgrids

In this paper, a weighted least square (WLS) state estimation algorithm with equality constraints is proposed for smart distribution networks embedded with microgrids. Since only a limited number of real-time measurements are available at the primary or secondary substations and distributed generation sites, load estimates at unmeasured buses remote from the substations are needed to execute state estimation. The load information can be obtained by forecasted and historical data or smart real-time meters. The proposed algorithms can be applied in either grid-connected or islanded operation mode and can efficiently identify breaker status errors at the main substations and feeders, where sufficient measurement redundancy exists. The impact of the accuracy of real and pseudo-measurements on the estimated bus voltages is tested with a 55-bus distribution network including distributed generation.

Assessment of influence of rolling mill FC-AR electric drive operation mode on 10kV supply network voltage quality

Advanced rolling mill electric drives are based on frequency converters (FC) with active rectifiers (AR). Operation of such converters has negative impact on the in-plant power supply system. To improve the voltage quality of active rectifiers, special algorithms of pulse-width modulation algorithms are used. As a rule, the study of the effect of electric drives with FC-AR on the supply network are carried out based on simplified mathematical models that do not consider possible resonance phenomena in the power supply system and operating mode of electric drives. Thus, the aim of the paper is to assess the acceptability of such an approach. The trends of the main parameters of the rolling mill electric drives have been recorded during the rolling cycle using the IBA PDA software. The obtained dependencies values have been approximated and applied in a complex simulation model of the in-plant power supply system. It considers the parameters of the supply network, cable lines, step-down transformers, rolling mill electric drives and other electrical receivers of the shop substations. The main assumption in simulation modeling is to consider the loads of other electrical receivers in the form of constant values. The authors have studied the effect of the operating modes of the rolling mill electric drive on the electric power quality in the 10 kV distribution network of the in-plant power supply system of a metallurgical enterprise. It is found that the total harmonic distortion KU at 10 kV sections of the main step-down substation of a metallurgical enterprise is changing in a nonlinear manner in the dynamic modes of acceleration and deceleration of electric drives. The nature of the coefficient KU also depends on the presence of resonance phenomena in the frequency response of the medium voltage supply network. The obtained results prove the need to consider the operating modes of electric drives when studying the influence of electric drives with FC-AR on the quality of the supply network voltage. in case we conduct experimental research using the equipment of the enterprises, as well as during theoretical research using mathematical models. The adequacy of the simulation model has previously been confirmed by experimental data and previous studies.

System Diagnostics of Supporting-Rod Porcelain Insulation at Digital Substations

This article is dedicated to an important problem of increasing the reliability of supporting-rod porcelain insulation at electric power substations. Porcelain insulation is installed on open switchgears (OSGs) of substations as part of the main switching equipment. Obsolescence and physical wear results in the destruction of supporting-rod porcelain insulators (SRIs), which often leads to serious consequences: shutdown of substation bus systems, emergency shutdown of substation equipment, reduction of power plant loads, as well as they pose a threat to operational personnel during operational switching. When supporting-rod insulation is replaced in due time, it significantly increases the reliability of the main substation equipment. Possible causes of failures were analysed using a graphical technique (Ishikawa diagrams). It has been established that sudden temperature changes of the ambient air are an important negative aspect, especially the transition of temperature values through 0ºC. The work represents a mathematical model of the development of microfractures in the insulation body of a ceramic insulator. The influence of external forces on the insulator leads to the appearance of additional stresses in it, to the destruction of new particles and to the sudden growth of microfractures. The article gives main SRI diagnostic techniques currently used in the electric power industry. According to statistics, it has been established that a relevant approach is the transition to digital technologies, which provides an automated information processing process without deactivating a piece of equipment. The article describes and proves that the proposed system of diagnostics of supporting-rod porcelain insulation at digital substations without deactivating a piece of equipment is a relevant area of scientific development. Within the framework of this scientific study, a patent for invention No. 2743887 dated 20 April 2020 was obtained.

Effect of distance relay settings on interference zone reading on 70 kV transmission lines Bolok - Maulafa using Digsilnet 15.1.7

Distance relay is the main protection relay on the 70 kV Bolok - Maulafa transmission line. Distance Relay works by comparing the impedance on the line when in normal or abnormal conditions with the impedance attached to the relay. If the relay detects an abnormal condition in the line, namely when there is a short circuit or other disturbance, the relay will work according to the settings. The relay setting itself is divided into several areas of the relay work zone to work selectively in reading the disturbances that occur. This study aims to see how distance relay adjustment (Impedance Adjustment) affects the reading of the fault zone when there is a short circuit fault on the line. The Bolok - Maulafa 70 kV transmission line is divided into two protection zones. By using DigSILENT 15.1.7, the impedance is obtained according to the type of conductor used. By using the setup guidelines found on Doc: PDM / SGI15: 2014, the new tuning value for the distance relay on the 70 kV Bolok - Maulafa transmission line is obtained as follows: the new adjustment value for zone 1 and zone 2 carrying bay Bolok - Maulafa amounting to 4,698˂70.18⁰ sec. Ohm and 13,658˂70.18⁰ sec. Ohm. As for the delivery of Maulafa - Bolok, it was 4,264 ˂70.18 ⁰ sec. Ohm and 6,076˂70.18⁰ sec. Ohm. This new adjustment is compared with the adjustment of PT PLN in reading the fault zone by the characteristic curve of each relay using DigSilent 15.1.7. There is a 3-phase short circuit at the 10% point in the direction of Bolok to Maulafa relay with PT. PLN at Bolok Substation and Maulafa Main Substation reads disturbances in zone 1. While the relay with new settings at the Bolok substation reads disturbances in zone 1, and the relay at Maulafa Substation reads disturbances in zone 2.

Design of Electrical Setting Protection System Indarung VI Cement Plant (Case Study New Cement Plant Construction at PT Semen Padang)

Along with the rapid development of technology and the development of civilization, electrical energy is very important in all fields. This research will conduct a study on the electrical protection system design of PT Semen Padang's Indarung VI Cement Plant using the ETAP 12.6 software. PT Semen Padang's Indarung VI Cement Plant uses three transformers of 150 / 6.3 kV of 30/35 MVA (ONAN / ONAF) and each Main Substation has substations that will supply all the loads to be used. The power flow study shows that the addition of a capacitor bank and a tap changer setting will improve the power factor and voltage of the system, thereby reducing the power supply sent by PLN. The short circuit study shows that the largest short circuit current, which is 35 kA, can be protected by a circuit breaker with a breaking capacity of 40 kA. The protection system coordination study shows that the results of the overcurrent relay setting can protect the electrical system of Indarung VI Cement Plant selectively and safely.