Distribution Network Feeder Research Articles

Analysis of shifting and reduction of the demand peak with the inserting of photovoltaic systems in the Neoville’s Headquarters of Federal University of Technology - Paraná Curitiba Campus

ABSTRACT Photovoltaic solar energy is increasingly present in the urban environment through the distributed generation. This kind of generation is characterized by the installation along the distribution network feeders, in low or medium voltage, and contribute to provide energy near the point of consumption. In this sense, this study aims to analyze the demand and consumption curves of the buildings of the Federal University of Technology - Parana (UTFPR) in the Neoville’s headquarters. The methodology consists in the application of COPEL's CAS Hemera platform, in order to determine the potential for the implementation of the Grid-Connected Photovoltaic Systems in this place, because they allow the reduction of costs with electric energy from the application of distributed generation. In February 2016, a grid-connected photovoltaic system was installed in one of the university’s blocks, which generated approximately 11 MWh of electric energy this year. This work proposes a scenario for the expansion of this photovotaic system and presents the contribution of photovoltaic generation, using the available coverage showing the shifting or reduction of energy demand peaks and the energy contribution to UTFPR's Neoville headquarters. The results of this study show that the proposed scenario will effectively change the profile of the university demand curve.

A Decentralized Local Flexibility Market Considering the Uncertainty of Demand

The role of the distribution system operator (DSO) is evolving with the increasing possibilities of demand management and flexibility. Rather than implementing conventional approaches to mitigate network congestions, such as upgrading existing assets, demand flexibility services have been gaining much attention lately as a solution to defer the need for network reinforcements. In this paper, a framework for a decentralized local market that enables flexibility services trading at the distribution level is introduced. This market operates on two timeframes, day-ahead and real-time and it allows the DSO to procure flexibility services which can help in its congestion management process. The contribution of this work lies in considering the uncertainty of demand during the day-ahead period. As a result, we introduce a probabilistic process that supports the DSO in assessing the true need of obtaining flexibility services based on the probability of congestion occurrence in the following day of operation. Besides being able to procure firm flexibility for high probable congestions, a new option is introduced, called the right-to-use option, which enables the DSO to reserve a specific amount of flexibility, to be called upon later if necessary, for congestions that have medium probabilities of taking place. In addition, a real-time market for flexibility trading is presented, which allows the DSO to procure flexibility services for unforeseen congestions with short notice. Also, the effect of the penetration level of flexibility on the DSO’s total cost is discussed and assessed. Finally, a case study is carried out for a real distribution network feeder in Spain to illustrate the impact of the proposed flexibility framework on the DSO’s congestion management process.

Electrical Distribution Industry - Long Term Load Forecast on Ilesha Road 11kV Feeder, Akure, Ondo State, Nigeria

This paper presents an investigative study on a selected 11 kV distribution feeder network in Akure township, Nigeria, aimed at evaluating power distribution problems and solution proposals for effective application of existing 11 kV feeders for power supply within Nigeria. Based on peak loads recorded on the feeder for 8 years a long term load forecast up to 2021 was carried out using “Trend’ and “Growth’ functions in Excel worksheet. These functions use Method of Least Squares. The peak network load is 8 MW and the expected load in 2021 is 14.5 MW (18.5 MVA at 0.8 power factor) after an exponential growth rate of 0.6 MW per annum. There is need to increase the rating of the power transformer feeding the feeder in order to enhance the security power supply to the network. Furthermore, the Power Company must provide standard input voltage (1.05x11 kV) to the network in order to normalize end-users voltage quality.

Investigation of Voltage Unbalance Profile in Low Voltage Electrical Distribution Network with Normal Mode Operation Using MATLAB

With ever increasing use of semiconductor devices and information technology (ICT) equipment in the industry, homes and offices, power quality is gaining attention to both industry and the electric utility. Power voltage quality cause huge economic losses to businesses all over the world. It is estimated to cost industry and commerce about €100 billion per annum in European Union, since voltage quality problem is one of the major power quality disturbances. This paper presents an investigative a study of the 11/0.4 kV, low voltage electrical distribution network and analyzes voltage unbalance. It recommends an effective method of improving the voltage profile and reducing the voltage unbalance to acceptable standard. The network was modelled using distribution network standard parameters for low voltage distribution network using MATLAB/Simulink sim power system tool box. The simulation results show that the percentage voltage unbalance, correct voltage profile and minimum voltage drop of 0.5 km distribution feeder line is of standard acceptable statutory limit, hence the distribution line operates at optimum performance. However, it is also established that the voltage profile for distribution network feeder lengths of 0.8 km to 5 km for balanced and unbalanced distribution lines from the beginning to the customer terminal of the distribution lengths are less than the acceptable allowable limit of – 5 %, of the nominal voltage value, hence voltages are inadmissible for customers use. Moreso, the percentage voltage unbalance, voltage profile and voltage drop on 0.8 km to 5 km distribution feeder line are all less than standard acceptable statutory limit, hence the distribution line operates below optimum performance. It was established that mitigating these problems require the electricity distribution company to install an effective voltage boosting devices along the network lengths in order provide admissible, permissible and normalize end users standard acceptable voltage.

Experimental Validation of a Steady State Model Synthesis Method for a Three-Phase Unbalanced Active Distribution Network Feeder

This paper presents the field validation of a method that performs steady-state model synthesis (SSMS) of active distribution networks using syncrophasor measurements. The validation is performed by applying the SSMS method on a real active distribution feeder network by utilizing the measurements from real phasor measurement units (PMUs) installed at the EPFL campus. An extended version of total vector error and a power flow comparison at the PMU buses are used as performance assessment metrics. A real-time hardware-in-the-loop simulations set up at the Distributed Energy System Laboratory is used for further performance assessment of the SSMS application. The effectiveness of the SSMS application is demonstrated by testing it extensively for several different case studies.

Earth fault location determination independent of fault impedance for distribution networks

Summary This article introduces a new earth fault location algorithm for both single and parallel feeders in distribution networks with single end measurements. The proposed algorithm depends on using the equality between the computed sequence components of the current at the fault point. The algorithm is independent of the dynamic arcing or static fault impedances. Then the faulted network can be decomposed into a prefault network and a pure fault network. The different types of connections of load transformer are considered in the study. This is because of their known influence on the direction of earth fault current in the faulty network. Moreover, the existence of distributed generation is considered during formulating the mathematical core of the proposed algorithm. Hence, the sequence current components at the faulty point can be derived without the need to measure the distributed generation current contribution or its terminal voltage with all varieties of load transformer connection. The proposed algorithm is tested via simulating a real 11 kV cascaded parallel-radial earthed distribution feeder from the Egyptian distribution network using Matlab. Different test cases are examined to visualize the performance of the proposed algorithm with a variety of fault conditions, including the fault impedance, loading, load transformer connection, and existence of distributed generations. All applied simulation tests ensure the efficacy of the proposed algorithm for estimating the fault distance in distribution systems with considerable distributed generation insertion and considering all possibilities of load transformer connection.

The value of conservation voltage reduction to electricity security of supply

In the specific event that there is not enough electricity being produced in the power market of Great Britain to meet demand, the system operator can use a set of mitigation tools to manage these supply shortfalls that are outside of normal operation of the market and that are used ahead of any controlled customer disconnections. Demand control is an emergency mitigation tool used by the system operator that instructs distribution network operators to implement voltage reduction across the electricity distribution system with the intent of achieving a reduction in customer's demand. The introduction of new low carbon generation and demand technologies in the electricity distribution networks, with fundamentally different technical and operating characteristics from the incumbent technologies, is likely to drive a dissimilar impact on the level of demand reduction that can be achieved through voltage reduction compared to those previously expected. Thus, there is a need to comprehensively understand the effectiveness of the voltage reduction in electricity distribution networks that can be realised through demand control events. The delivery of demand control can be achieved through conservation voltage reduction (CVR) techniques based on the principle of lowering the supply voltage to end-use consumers of electricity in order to reduce the energy consumption of some types of loads while maintaining customer service voltage within statutory limits. This paper presents a methodology to quantify and assess the value of CVR to security of supply of electricity systems. Specifically, it estimates the response of electricity demand to demand control events in the electricity distribution system to reduce customer's demand during periods of significantly low supply-demand margins. The methodology is applied to a network structure representative of the electricity distribution network of Great Britain and the value of CVR is estimated for individual distribution network feeders and for the distribution system over an annual load cycle. The analysis demonstrates that the response of demand to voltage reduction is relatively different from substation to substation, feeder to feeder and especially load to load. The CVR factor for the Great Britain electricity distribution network is assessed to vary on average from 0.81 in the summer season to 1.13 in the winter season. The CVR factors for the electricity distribution network of Great Britain are expressed in the form of a look up table to provide a simple framework for network operators to estimate the response of demand to voltage reduction/demand control events.

An inverse‐time low‐impedance protection design for feeders in active distribution networks

One of the major issues associated with active distribution networks (ADNs) is to devise an appropriate protection scheme that works successfully in different operation modes. This paper describes the design of an inverse‐time low‐impedance (ITLI) protection scheme with the aid of the advanced measurement technologies in ADNs. The scheme detects faults and calculates tripping time by using the magnitude ratio of the maximum load impedance to the measured impedance. ITLI protection is immune to varying fault current caused by the flexible operation modes and able to automatically adjust fault‐tripping time according to the fault severity. With the existing communication infrastructures, an event‐triggered adaptive setting scheme updates the settings of ITLI relays in real time. The setting method not only enhances the detecting capability but also provides higher reliability and sensitivity before, during, and after events in ADNs, such as tap position adjustment, DGs fluctuation, and network structure change. Besides, an acceleration method based on the definite‐time grading technique is presented to reduce the impact of infeeds and fault resistance. The effectiveness of the proposed protection scheme is demonstrated in a 12.47‐kV active distribution network established by PSCAD/EMTDC. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Multi-agent based Demand Response management system for combined operation of smart microgrids

Abstract This paper presents an agent based market model for combined operation of the grid connected smart microgrids with price sensitive consumers by executing demand side management strategies. This model maintains a non-discriminative market environment among the consumers and generators of the microgrids connected across the distribution system. The novelty of this agent model is in two fold. First, a novel incentive mechanism called priority banking is proposed to encourage the consumers by giving them a share in locally available generation. This mechanism also monitors how often the consumers are utilizing the incentives and thereby updates their priority. Second, after executing the contracts obtained from the market, the loss contribution of each trade to the overall network loss is calculated using a novel network loss allocation method. The applicability and effectiveness of the proposed agent based market model are exemplified using an IEEE 37 bus distribution feeder network with two grid connected smart microgrids simulated in Open DSS and the proposed multi-agent system is built on JADE framework.

KOORDINASI SETTING RELAI ARUS LEBIH PADA INCOMING 2 KUDUS TERHADAP OUTGOING KUDUS 5 DAN 6 YANG MENGGUNAKAN JARINGAN DOUBLE CIRCUIT DI GI 150 KV KUDUS

Sartika Kusuma Wardani, Subali, in paper coordination of flow over relay setting in incoming 2 kudus to outgoing 5 and 6 using double circuit network on GI 150 KV kudus explain that PT PLN make every effort to improve service to customers , one of them by increasing the reliability of the distribution of electrical energy . Reliability of the distribution network is very important for both consumers and PLN. One measure of the reliability of the system / network is a factor SAIDI (System Average Interruption Duration Index) and SAIFI (System Average Interruption Frequency Index). Steps that have been done one way to minimize the possibility of interference is by installing protective devices on medium voltage networks. However, installation of protection equipment is not enough if the relay setting coordination between the incoming and outgoing imprecise. In fact in recent months, an interruption in the feeder distribution network which affects the incoming relay tripnya due to failure of the feeder protection system. One of the events that have happened several times is the same disorder in a double feeder circuit (network supplied from a single source by using two networks ( two feeder ) were included in the bus and in 1 pole) and holy 5 and 6 which causes the incoming PMT trip. It is very risky to happen, because the resulting trip relays at all incoming feeder that gets supply voltage of the incoming. So it takes coordination of overcurrent relay settings right so that the incidence of the incoming trip Sacred 2 does not happen again . Keywords: distribution, protection, relay settings, incoming, outgoing

Risk-based maintenance scheduling in the presence of reward penalty scheme

In the recent years, the regulators employ various forms of reward/penalty schemes (RPS) in electric distribution networks to ensure the reliability of services. In the presence of RPS, distribution system operators (DSOs) would be exposed to financial penalty if they cannot provide reliable service to the customers. This means that the uncertainty in the reliability of services shows itself in financial risk faced by DSO. In such circumstance, DSOs are induced to reinforce the reliability of service through reliability reinforcement projects such as preventive maintenance (PM) projects. The maintenance projects should be managed in a way that the maximum profit can be obtained in the minimum risk. This study introduces risk-based maintenance management in the presence of RPS.Modeling the dependency of component failure rate on the preventive maintenance (PM) expenditure is the core of risk-based maintenance management, and this paper introduces the generalized proportional failure rate model (GPFM) for this purpose. This model together with the outage time generation algorithm (OTGA) help us to determine the financial risk faced by DSO.To verify the proposed method, it was implemented in the overhead line (OHL) feeders of a real distribution network.

Layered Model Algorithm and its Application in Fault Detection of Power Distribution Network

In the case that a single fault occurs on a power feeder in the one-source distribution system, the directional layered model of the network which reflects the layered topological characteristic of the network was built up. Then a new algorithm for fault detection in power distribution network was proposed to locate the faulty sections in distribution feeder network. The algorithm itself as well as its program design is simple. It can be applied to complex distribution systems with multi-sources. It is proved correct by an example.

Fault section estimation in power distribution network using impedance‐based fault distance calculation and frequency spectrum analysis

In this study, a practical method is proposed for determining the distance and the section of fault in power distribution system (PDS). In the suggested method, at first the possible fault points are determined using a novel impedance-based fault location method. Since the number of these points may be more than one, thus two methods are proposed for determining the real location of fault. In the first method, the measured and recorded samples of voltages at the beginning of feeder for actual fault are compared with the stored samples of voltages which are obtained from simulating of fault at the possible fault points. The one with highest matching is the real location of fault. In the second method, frequency spectrum (FS) of voltage is defined as a suitable criterion for this purpose. Therefore the real fault point is determined by comparing and matching the FS of voltages obtained from the simulated faults and the recorded voltage for actual fault. The performance of the proposed method is evaluated in a real feeder in distribution network of Iran considering different types of faults, fault resistances, fault inception angles, real instrument transformer models and X/R ratio changes of upstream PDS network. The obtained results show that the performance of the proposed method is quite satisfactory and its accuracy is very high.

Applying Dynamic Load Estimation and Distributed-parameter Line Model to Enhance the Accuracy of Impedance-based Fault-location Methods for Power Distribution Networks

Precise load modeling and load value estimation at each node of power distribution systems are very important for determining the exact location of fault in impedance-based fault-location algorithms. In this article, a modified impedance-based fault-location algorithm is proposed by applying dynamic load estimation and distributed-parameter line model. The load value at each node is estimated by its load factor and power factor. In the proposed fault-location algorithm, the power distribution system and power factor of each node are estimated first, just before the fault, using the recorded data of voltage and current at the beginning of the main feeder. Then, using this information, the initial location of the fault is obtained by analyzing each section. In this process, multiple positions for the fault can result. Thus, the faulted section is determined by analyzing the operation of protective equipment, i.e., fuses, fault indicators, and reclosers, performed by investigating the current patterns at the beginning of feeder. The performance of the proposed method is evaluated based on a real feeder in an Iranian distribution network under different fault conditions. The obtained results show the efficiency and accuracy of the proposed method.

Optimal Power Market Participation of Plug-In Electric Vehicles Pooled by Distribution Feeder

Electric-vehicle grid integration has the potential to stress distribution network equipment and increase peak consumption, unless properly managed. In this paper, we use dynamic programming to develop a decision support algorithm and market participation policy for a load aggregator (LA) managing the charging of plug-in electric vehicles (PEVs) connecting at the same distribution network feeder. The LA submits inflexible and flexible bids to a liberalized hour-ahead power market, while monitoring localized feeder and PEV rate constraints. Flexible bids, which include a bid price or utility, can be cleared as regulation service, cleared as energy, or rejected by the market operator. These market events are probabilistically included within the modeling framework. A case study, based on New York independent system operator data, found that the market participation policy may reduce daily electricity costs for PEVs significantly more than is expected through forecasted electricity-price-based scheduling.

Reliability Programming of Distribution Network Feeder Switches Based on Pareto Optimality Theory

Reliability Programming of Distribution Network Feeder Switches Based on Pareto Optimality Theory

A Study on Real-Time Pricing Method of Reactive Power in Voltage Profile Control Method of Future Distribution Network

It is of prime importance to solve the voltage maintenance problem caused by the introduction of a large number of distributed generators. The authors have proposed “voltage profile control method” using reactive power control of distributed generators and developed new systems which can give economical incentives to DG owners who cooperate the voltage profile management in the previous works. However, it is difficult to apply the proposed economical systems to real-time operation because they are based on the optimization technology and the specific amount of incentive is informed after the control action has finished. Therefore, in this paper, we develop a new method that can determine the amount of incentives in real-time and encourage the costumers to cooperate voltage profile control method. The proposed method is tested in one feeder distribution network and its effectiveness is shown.

Determination of loss‐minimum configuration with mathematical optimality in a three‐sectionalized three connected distribution feeder network

AbstractIn a distribution system, in order to enhance the reliability of power supply, the distribution feeder is divided into several sections by installing sectionalizing switches, and then each of the sectionalized sections is connected to a different feeder. For example, one feeder is divided into three sections by two sectionalizing switches, and then each of the divided sections is connected to the other feeder through sectionalizing switch. Since a distribution system with many feeders has many sectionalizing switches, the system configuration is determined by states (opened or closed) of sectionalizing switches. Usually, a power utility tries to obtain distribution loss‐minimum configuration among large numbers of configuration candidates. However, it is very difficult to determine the loss‐minimum configuration such that the mathematical optimality is guaranteed, because it is well known that determination of a distribution system's configuration is to decide whether each sectionalizing switch is opened or closed by solving a combinatorial optimization problem.In this paper, the authors propose a determination method of loss‐minimum configuration by which the mathematical optimality is guaranteed for a three‐sectionalized three‐connected distribution feeder network. A problem to determine the loss‐minimum configuration is formulated as a combinatorial optimization problems with four operational constraints ( feeder capacity, voltage limit, radial structure, and three‐sectionalization). In the proposed method, after picking up all partial configurations satisfied with radial structure constraint by using enumeration method, optimal combination of partial configurations is determined under the other operational constraints by using conventional optimization method. Numerical simulations are carried out for a distribution network model with 140 sectionalizing switches in order to examine the validity of the proposed algorithm in comparison with one of conventional meta‐heuristics (tabu search). © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 56– 65, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20530

Feeder load balancing using fuzzy logic and combinatorial optimization-based implementation

The distribution system problems, such as planning, loss minimization, and energy restoration, usually involve the phase balancing or network reconfiguration procedures. The determination of an optimal phase balance is, in general, a combinatorial optimization problem. This paper proposes a novel reconfiguration of the phase balancing using the fuzzy logic and the combinatorial optimization-based implementation step back to back. Input to the fuzzy step is the total load per phase of the feeders. Output of the fuzzy step is the load change values, negative value for load releasing and positive value for load receiving. The output of the fuzzy step is the input to the load changing system. The load changing system uses combinatorial optimization techniques to translate the change values (kW) into number of load points and then selects the specific load points. It also performs the inter-changing of the load points between the releasing and the receiving phases in an optimal fashion. Application results using the distribution feeder network of South Africa are presented in this paper.

数理的最適性が保証された3分割3連系配電損失最小構成の決定手法

数理的最適性が保証された3分割3連系配電損失最小構成の決定手法