Distribution Substation Research Articles

Management of Charging Load of Electric Vehicles for Optimal Capacity Utilisation of Distribution Transformers

A de-centralised load management technique exploiting the flexibility in the charging of Electric Vehicles (EVs) is presented. Two charging regimes are assumed. The Controlled Charging Regime (CCR) between 16:30 hours and 06:00 hours of the next day and the Uncontrolled Charging Regime (UCR) between 06:00 hours and 16:30 hours of the same day. During the CCR, the charging of EVs is coordinated and controlled by means of a wireless two-way communication link between EV Smart Charge Controllers (EVSCCs) at EV owners’ premises and the EV Load Controller (EVLC) at the local LV distribution substation. The EVLC sorts the EVs batteries in ascending order of their states of charge (SoC) and sends command signals for charging to as many EVs as the transformer could allow at that interval based on the condition of the transformer as analysed by the Distribution Transformer Monitor (DTM). A real and typical urban LV area distribution network in Great Britain (GB) is used as the case study. The technique is applied on the LV area when its transformer is carrying the future load demand of the area on a typical winter weekday in the year 2050. To achieve the load management, load demand of the LV area network is decomposed into Non-EV load and EV load. The load on the transformer is managed by varying the EV load in an optimisation objective function which maximises the capacity utilisation of the transformer subject to operational constraints and non-disruption of daily trips of EV owners. Results show that with the proposed load management technique, LV distribution networks could accommodate high uptake of EVs without compromising the useful normal life expectancy of distribution transformers before the need for capacity reinforcement.

A PCA-Based Consistency and Sensitivity Approach for Assessing Linkage Methods in Voltage Sag Studies

In the light of Brazilian energy regulatory context, cluster strategies are required to classify groups of substations for voltage sag purposes. Tuning cluster algorithms is not a trivial task, due to the fact that these methods are sensitive to small errors. Therefore, this study proposes a new methodology based on principal components analysis (PCA), attribute agreement and analysis of covariance to verify the level of consistency and sensitivity of the linkage methods in the cluster formation for voltage sag studies. In order to prove this methodology, real data from power quality indices of distribution substations are used. Four distinct scenarios with disturbances are evaluated. PCA is applied for dimensionality reduction of the data. Then, grouping is performed for eight different linkage methods and agreement analysis is applied. Ward method was the only one that presented 100% consistency in all scenarios, considered as the most robust method whereas k-means showed consistency of 94.11%, with inversion of the clusters. However, when evaluating their groupings, it was found that k-means was unable to adequately separate the groups for this dataset. Finally, the proposed methodology is adequate for choose cluster methods for extensive data and it can be extended to applications in different areas.

Interference Analysis of Medium Voltage Air Line 20 KV Feeder Using Failure Mode and Effects Analysis Method

This article discusses the interference analysis of medium voltage air line 20 kv feeder using failure mode and effects analysis method. The distribution network consists of two parts, the first the distribution network consists of two parts, the first is the medium / primary voltage (JTM) network, which supplies electrical power from the sub-transmission substation to the distribution substation, the primary distribution network uses three wires or four wires for three phases. the impact of the reliability index from the calculation of the impact of the reliability index based on the number of disturbances (SAIFI), it shows that in January 2019 it has the highest index value, namely SAIFI, 1,695 disturbances/ subscribers. From the results of the calculation of the impact of the reliability index based on the number of blackouts (SAIDI), it shows that in January 2019 the SAIDI index value was 3,883 hours/customer.

A UHF Sensor Based Partial Discharge Monitoring System for Air Insulated Electrical Substations

A Partial Discharge (PD) monitoring system for Air Insulated Substations (AIS) has been developed for monitoring of partial discharge activities of various insulators and insulating media that are distributed over an electrical substation. The proposed system utilizes four UHF sensors, which are to be placed around the area of interest so that any impulsive UHF signal originated from PD activity can be captured and subsequently processed for detection and localization of multiple PD sources. To improve the localization accuracy and to improve the detection specificity, i.e. to eliminate false impulsive UHF signals originated from other sources, a novel nearest-neighbour based approach is proposed, which utilizes the physical layout of the AIS to identify most probable PD source locations. The proposed algorithm can accurately find the PD source locations even in the presence of high time-delay-of-arrival (TDOA) estimation error by making necessary corrections in the PD source location estimation. The proposed algorithm has been field trialed in many small and medium-size distribution substations. A detailed comparative study with the other algorithms in different extreme situations has been performed with the help of simulation and laboratory-based testing. The obtained results are worthwhile for supporting widespread implementation of the proposed method.

Analisis Voltage Drop Pada Jaringan Tegangan Rendah Dengan Metode Pecah Beba Pada Gardu KH 007 Di PT PLN (Persero) UP3 Pamekasan

In the operation of the electric power system, good quality service is needed. One of them is thevoltage value received by the customer does not get a voltage drop. Based on SPLN No.1: 1978, theservice voltage is a maximum of 5% and a minimum of 10% of the nominal voltage of the LowVoltage Network that is 220 Volt. One of the locations experiencing voltage drop problems is on theCentral Pakandangan Village, Sumenep. Based on an analysis do by the PT PLN UP3 PamekasanNetwork division, it turns out that the voltage drop that occurred on Central Pakandangan Villagecaused by the location. The location is to far from the KH 007 distribution substation, which is 643meters. Then, the area around the location also has a high burden due to the many standingresidential settlements. Therefore, it is necessary to break the load on the network. This method isdone by moving or transferring part of the load from the old network to the new network. Which isthe last 5 poles in this line. so the load supported by one line does not have voltage drop. The resultobtained after performing the load break is that the voltage on the receiving side rises to phase R200 Volt, phase S 212 Volt, and phase T 202 Volt. Where previously the value of the voltage on thereceiving side is phase R 189 Volt, phase S 206 Volt, and phase T 194 Volt.

Integrated linear reactor in transformer based on non-orthogonal decoupling method

The air-core reactor has the advantage of good linearity and low noise, however the problem of large space occupation. Power filter with the air-core reactor is indispensable with the widespread use of the power electronic devices in electrified transportation system and urban distribution system. It is hoped that the air-core reactor can be integrated in the transformer to reduce the space while the good performance of the power filter is kept. In this paper, a non-orthogonal decoupling (NOD) method is proposed, as well as a new design to integrate the linear reactor based on it. Further research including the structure of the integrated linear reactor (ILR) windings, the mechanism of the power decoupling among windings and the calculation of the inductance values are introduced. A 3-D finite-element simulation model is established which demonstrate the correctness of the analysis and provided an assistant approach of engineering design. Finally, the prototype system of the box-type distribution substation with integrated filter reactor and its experimental date are shown, the distribution transformer with integrated air-core reactors are confirmed to have excellent performance.

EVALUASI JARINGAN TENGANGAN MENENGAH PASCA BENCANA DI KABUPATEN HALMAHERA SELATAN

This study looked at the condition of power loss and falling voltage after the evaluation of the medium voltage network 20 kV after the earthquake disaster in South Halmahera district, especially in labuha extension on Bacan island The method used in this study is a quantitative research method with data collection done which is then simulated using ETAP 12.6 software. The simulation result obtained total power loss at Labuha extension is 44.3 kW + 66.8 kVAR or 80,154 kVA of 2,445 MVA delivery power, while the presentation of power loss is 3.278%, this is still considered feasible because the power loss on the medium voltage network 20 kV is 10% while in Labuha turtles the power loss is less than 10%. While the large fall in voltage at the largest Labuha extension at the Belang-Belang distribution substation is 3.96% or 792 volts, this is due to the channel length and presentation of the load reaching 83% against the distribution tranformator and the fall in the average voltage of Labuha's purgator is 3.025% or 605 volts against the nominal voltage of 20 kV. It is still considered viable for operation due to the permitted voltage fall on the 20 kV medium voltage network which is 5%.

Impact of Photovoltaic System Integration on Low Voltage Network

In this paper, we perform an analysis of the Photovoltaic penetrations on Low Voltage Power Distribution Networks. A case study of the East Legon Power Distribution Services M05/52 LV Network. The impacts of high photovoltaic penetration on voltage level and power factors are explored. We fixed power quality analyzers at the distribution substation and at the customers’ nodes; to capture the feeder loads and the voltage profiles. Simulations are done at varying photovoltaic penetrations levels to determine the strike of increasing photovoltaic incursion on the low voltage power network. We present results to show that, the optimum penetration level is achieved at the point where minimum loss reduction is recorded, reverse flow not present and power factor limit is not violated.

Review analysis on cloud computing based smart grid technology in the oil pipeline sensor network system

Natural resources plays efficient contribution in the human world in the way of consuming energy resources for the daily life cycle. The main concerns rely on the transporting oil from refining to the consumer usages through different modes. In the transportation passages, its performances are calibrated in the robust manner through sensor network communication and the periodical pigging inspection on the pipeline system. This chapter enumerates about the layout of oil pipeline system and its sensor measurement and instrumentation deliberately placed on the long run pipelines. The evolution of smart grid application enhances this oil transportation in a much corporate band by accumulatively orienting the sensor network in the utilization of power resources. Further, through the wireless communication associated with the smart grid, the pigging inspection gauges are exploited in the desired geographical area with better power consumption. Existing research on communication technologies in SG is briefly overviewed with the main focus on Cloud computing approaches. In this paper, the Smart Grid architecture and its applications are focused on entire oil pipeline from inlet to distribution substations first. The Cloud Computing architecture is explained thoroughly. Then, Cloud Computing for Smart Grid applications are also introduced in terms of efficiency, security and usability. Cloud platforms technical and security protocols are analyzed. Finally, the inspection of oil pipeline system by receiving sensor data of smart pigs incorporated with the cloud computing technique associated with smart grid application is elaborated with its SCADA hierarchical architecture. Further, simulation analysis of wireless sensor nodes with Flexmeter platform for power monitoring over smart pig case scenario is also presented with its layer-wise characterization.

Methodology for Predictive Assessment of Failures in Power Station Electric Bays Using the Load Current Frequency Spectrum

This paper presents a novel analysis methodology to detect degradation in electrical contacts, with the main goal of implanting a predictive maintenance procedure for sectionalizing switches, circuit breakers, and current transformers in bays of electric transmission and distribution substations. The main feature of the proposed methodology is that it will produce a predictive failure indication for the system under operation, based on the spectral analysis of the load current that is flowing through the bay’s components, using a defined relationship similar to the signal-to-noise ratio (SNR) used in data communication. A highlight of using the proposed methodology is that it is not necessary to make new investments in measurement devices, as the already-existing oscillography measurement infrastructure is enough. By implementing the diagnostic system proposed here, electrical utilities will have a modern tool for monitoring their electrical installations, supporting the implementation of new predictive maintenance functions typical of the current electrical smart grid scenario. Here, we present the preliminary results obtained by the application of the proposed technique using real data acquired from a 230 kV electrical substation, which indicate the effectiveness of the proposed diagnostic procedure.

Simulation-Based Evaluation of the Performance of Broadband over Power Lines with Multiple Repeaters in Linear Topology of Distribution Substations

Broadband over Power Lines (BPL) is considered a promising communication technology in the concept of Smart Grids. This paper evaluates networks based on BPL, with a focus on the impact of repeaters in the linear topology of distribution substations. In large-scale Smart Grids network planning, positions of repeaters have to be carefully chosen. This article should help to determine such positions and limitations of BPL linear topology networks. Laboratory and on-field measurements and their results are presented in this article. Results show the impact of repeater’s deployment for different testing methodologies also with regard to other already presented studies. Measured values and the determined impacts of repeaters are later used as input data for simulation of the linear BPL topology in terms of network throughput with multiple streams and bottlenecks. These occur especially on lines shared by multiple communicating nodes. Furthermore, the simulation investigates the balancing time of multiple data streams throughput. The simulation shows that the throughput balancing can occupy a significant time slot, up to tens of seconds before the throughput of different streams balances. Also, the more data is generated, the more time the balancing time takes. Additionally, the throughput drop caused by a repeater is determined into the range of 35–60%. Based on the measurement and simulation results, lessons learned are presented, and possible performance improvements are discussed.

Risk‐based approach for power transformer replacement considering temperature, apparent age, and expected capacity

Due to the limited availability of end-of-life failure data of power transformers by electric utilities, planning the replacement of power transformers is a challenging task for utility engineers. Transformers can be replaced based on their health indices, but they do not allow utility engineers to quantify risks posed by transformer failures. In that context, the study proposes a novel risk-based approach to plan the replacement of aged power transformers considering their temperature, apparent age, and expected capacity. The approach comprises a methodology that incorporates power transformers' winding hottest-spot temperature and apparent age into the conventional end-of-life failure model, a methodology that calculates the expected capacity of power transformers, a novel transformer ranking index, and a methodology that calculates the optimum year of replacement. Subtransmission and distribution substations were included in the IEEE Reliability Test System to evaluate the performance of the approach. The results show that incorporating the winding hottest-spot temperature and the apparent age into the end-of-life failure model can make a significant improvement on transformer replacement decisions in the event of limited availability of failure data. Results further suggest that end-of-life failures of fans and oil pumps can have an impact on the prioritisation of transformer replacement.

Monitoring of low voltage grids with multilayer principal component analysis

This article presents a monitoring strategy based on multilayer principal component analysis (PCA) to detect and diagnose power system disturbances in large amounts of data collected by intelligent electronic devices in low voltage smart grids. The PCA models are built on multiple sliding windows, sized (in terms of length and sampling time) according to the type of phenomena to detect. Abnormalities are detected with use of two complementary statistical indexes, then diagnosed by computing the individual contributions of each monitored variable to the constraint violation of those statistics. As a result, its implementation enables an automatic analysis of multiple phenomena of interest in parallel over time using distinct electrical quantities. Furthermore, the method is demonstrated within the RESOLVD project with data from the OpenLV project containing measurements of active and reactive power gathered at different low voltage distribution substations.

DESAIN SISTEM OTOMATISASI POMPA MENGGUNAKAN PICOBOX DI PDAM KOTA DENPASAR

One of the uses of water resources can be done through the Regional Water Company(PDAM). Equipment needed in a water supply system that uses wells as a source of waterinclude well pumps, booster pumps, and pump control systems so that the pumps can workeffectively and efficiently. The Operation and Maintenance Section is still using a manualsystem in carrying out its duties by coming to the location and immediately conducting aninspection. This study designed a pump automation system with Aplus Massenger picobox toolusing an SMS service. The pump automation system consists of a series of microcontrollers,GSM modules, RTC modules, and electric current sensors. SMS information on the value of theload current at the distribution substation is sent by the pump automation system according tothe sensor reading information and the time information set on the system. The load currentnotification system can provide an SMS warning of a disturbance of the load current at thedistribution substation. This pump automation system is carried out in the Treatment Room ofthe Water Treatment Pump Distribution Unit in the Denpasar City PDAM, with the result of anSMS reply in the form of "load current: 30-10-2019” is R = 64 Amperes, S = 63 Amperes, T = 64Amperes to receive the information about the value of the load at the distribution substation.

A coherent strategy for peak load shaving using energy storage systems

Abstract In recent years, balance of power supply and demand as control and smoothing of peak load demand has been one of the major concerns of utilities. Hence, peak load shaving is a preferred approach to cut peak load and smooth the load curve. This paper presents a novel and fast algorithm to evaluate optimal capacity of energy storage system within charge/discharge intervals for peak load shaving in a distribution network. This method is based on reshaping of aggregated load profile (historical load profile), which observed from the main distribution substation to calculate required BESS size by simple and fast mathematical procedures. A case study of 22-bus model is analyzed in MATLAB® environment to determine optimal location of the selected BESS. Main contribution of this paper is (ⅰ) to find the optimal size (capacity and power) of BESS, (ⅱ) determine the optimal location of BESS, and (ⅲ) propose the BESS control strategy and scheduling for optimum operation. Different scenarios including the baseline case (without BESS), centralized BESS, and centralized BESS with PV are considered to reduce peak load demand and power losses, as well as to improve voltage profile during peak load hours. Simulation results indicate that all cases of BESS installation can significantly improve the operation of the distribution network. Simulation results highlight centralized BESS and PV as a compelling case to shave demand peak. All told, findings indicate the effectiveness of the proposed algorithm for peak load shaving by giving optimum location and sizing of BESS.

A constraint-based approach for optimizing the design of overhead lines

The use of computational methods in engineering design is a long-standing issue. Several mathematical approaches have been investigated in the literature to support the design optimization of engineering products. Most of them are focused on the optimization of a single structure, without considering a system of structures. The design of supports for electric lines requires tools for the management and sizing of a system of structures that interacts with each other under specific load conditions. This paper deals with a framework to support the design optimization of an overhead line using methods related to the theory of the Constraint Satisfaction Problem. The object-oriented model of a transmission line has been described and then implemented into a prototypical software platform. The parameters to be considered as variables are defined by the designer at the beginning of the optimization process. These variables are geometrical dimensions, poles locations, cable pre-tension, etc. The set of constraints is related to normative, climate conditions, datasheets, material limits, and expert knowledge. To demonstrate the effectiveness of this approach, a case study has been developed considering a variable number of constraints and parameters. In particular, the case study is focused on the design of a low-voltage sub-network between two distribution substations.

Dynamic Inspection Interval Determination for Efficient Distribution Grid Asset-Management

Asset-management accounts for a significant share of grid operators’ influenceable costs, which are under high economic pressure due to deregulation. In asset-management, visual inspections are the main measure to determine asset conditions. In the context of digitalization, we propose a concept to acquire additional information about the condition of distribution substations and to derive flexible inspection intervals from this information, in contrast to fixed intervals that are common in scientific literature and practice. Thus, knowledge about the substations increases, inspection intervals can be expanded dynamically, and significant cost savings are possible, which we demonstrate by the example of a German distribution grid operator.

ELECTRICAL LOAD RELIABILITY ASSESSMENT USING ANALYTICAL METHOD, CASE STUDY: FUPRE 1 X 2.5MVA INJECTION SUBSTATION

This research work presents the reliability assessment of electrical load distribution system in Federal University of Petroleum Resources, Effurun (FUPRE), Warri using the Analytical method and ETAP software as the simulation tool to run the reliability assessment of the System. The analytical analysis was conceded out by using August 2018 – August 2019 historical data of Tetfund Classrooms Blocks, Hostels, College of Technology, Administration Block, Health Center, and College of Science Feeder obtained from the Benin Electricity Distribution Company [BEDC]. The results conceded revealed that College of Technology Injection Substation is the most reliable in the distribution network when compared to the other five substations around the institution premises as it recorded system indices of ASAI: 99.30, SAIFI: 1.10, SAIDI: 55.35, CAIDI: 123.04 in August 2018 to August 2019. Nevertheless, the total reliability indices of the six substations under investigation as obtained from the analysis, and it shows that availability of power to FUPRE distribution is very poor as compared with the benchmark of IEEE ASAI of 99.99 for distribution substation availability.

Optimal Modeling and Allocation of Mixed Wind and Solar Generation Systems in Electric Distribution Networks

Electric power generated in a centralized station is transmitted through the transmission system and supplied to the consumer end through an electric distribution substation. Electric power losses are high in distribution network compared to the transmission system. The integration of decentralized generation (DG) units in electric distribution networks will reduce power losses. However, the integration of conventional DG is not appreciable due to various techno-economic and environmental concerns. Hence there is a need for the changeover from conventional to renewable energy sources (RES) for energy requirement. Because of vast availability, non-polluting nature, and sustainable character of RES are grasping significant attention over the years. At present most, viable RES are solar and wind energy systems in the world. It is observed that the output generation patterns of solar photovoltaic (PV) arrays and wind turbine generation units (WTGUs) are arbitrary. Hence there is a need for sophisticated method/technique for modeling these generated outputs. In the present paper, optimal modeling and allocation of RES are solved using a novel metaheuristic algorithm. The proposed algorithm is tested on 12, 15 and 85 – bus radial distribution networks (RDNs) and the simulation results obtained are outperforms other existing techniques in the literature.

Probabilistic evaluation of distribution power transformers reliability indices considering load transfers and mobile unit substations

This paper proposes a new and practical probabilistic method for calculating reliability indices and costs associated with distribution substations that share spare transformers of a same group. Based on Monte Carlo simulation, the proposed algorithm considers the chronological representation of failure occurrences, and enhances previous methods by modeling emergency actions, such as transferring load to neighboring feeders and connecting a mobile unit substation to ensure electricity supply to customers during the replacement of failed transformers. Thus, spare transformer requirements with new acquisitions to replenish the stock or even to expand the system are probabilistically assessed. All waiting times associated to these actions can be duly represented by any probability distribution, including the usual exponential model. A more accurate calculation of reliability indices and costs associated with the interruption of consumers is achieved. The corresponding computational algorithm is used in several numerical applications, considering a class of transformers of a Brazilian electricity utility. The results of these applications are deeply discussed to demonstrate the practical relevance of the proposed method.