Customer Interruption Costs Research Articles

Improving reliability by focusing on the quality and condition of medium-voltage cables and cable accessories

The study presents the processes and technologies that are used in the asset management of MV (medium voltage) underground cable network to maintain the cable assets in a good condition. In order to offer good premises for distribution networks with a high reliability and a long lifetime, the commissioning and installation quality is essential. The procedures how Helen Electricity Network Ltd (Helen) has achieved and maintained the low failure rate in a medium-voltage network is described. This development in the processes of Helen has decreased the failure rate in the newly installed network and thus has decreased the customer interruption costs and the costs in the corrective maintenance.

Reliability Optimization of Automated Distribution Networks With Probability Customer Interruption Cost Model in the Presence of DG Units

Distribution automation systems in terms of automatic and remote-controlled sectionalizing switches allows distribution utilities to implement flexible control of distribution networks, which is a successful strategy to enhance efficiency, reliability, and quality of service. The sectionalizing switches play a significant role in an automated distribution network, hence optimizing the allocation of switches can improve the quality of supply and reliability indices. This paper presents a mixed-integer nonlinear programming aiming to model the optimal placement of manual and automatic sectionalizing switches and protective devices in distribution networks. A value-based reliability optimization formulation is derived from the proposed model to take into consideration customer interruption cost and related costs of sectionalizing switches and protective devices. A probability distribution cost model is developed based on a cascade correlation neural network to have a more accurate reliability assessment. To ensure the effectiveness of the proposed formulation both technical and economic constraints are considered. Furthermore, introducing distributed generation into distribution networks is also considered subject to the island operation of DG units. The performance of the proposed approach is assessed and illustrated by studying on the bus 4 of the RBTS standard test system. The simulation results verify the capability and accuracy of the proposed approach.

On Exploring Potential Reliability Gains Under Islanding Operation of Distributed Generation

The paper presents a subislanding approach based on two algorithms, a backtracking algorithm, which is used to detect the exact location of distributed generation based on renewable energy sources (DGRESs) to establish subislands in the distribution networks and a protection co-ordination algorithm, which is used to identify the fault location. The IEEE reliability busbar test system is used for algorithm qualification, with several case studies and sensitivity analyses employed to verify the proposed algorithms. The probabilistic-based analytical technique along with the customer interruption cost model is then used to evaluate reliability improvements. The results presented in the paper indicate that the proposed approach is effective in increasing the reliability of power distribution systems with high penetration of DGRESs while providing an online reliability assessment.

Simultaneous Distributed Generation Placement, Capacitor Placement, and Reconfiguration using a Modified Teaching-Learning-based Optimization Algorithm

In this article, a modified version of the teaching–learning-based optimization algorithm is proposed for a combined optimization problem: simultaneous distributed generation (DG) scheduling, capacitor sizing, and reconfiguration of distribution networks to minimize active power loss and maximize reliability of the network. The objective of loss reduction is modeled as the benefit of not purchasing active power from the transmission grid. Customer interruption cost reduction is also used as the reliability improvement index. In this article, a new method for customer interruption cost calculation based on the bus injection to branch current (BIBC) matrix and Dijkstra's path-finding algorithm is proposed for different network topologies. The proposed approach is applied on a 69-bus test system that has been used in many previous studies. The results of the modified teaching–learning-based optimization are compared with those of some other optimization methods, including the conventional teaching–learning-based optimization algorithm. The results demonstrate the superiority of the proposed method and approach.

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Analytical FRTU deployment approach for reliability improvement of integrated cyber‐physical distribution systems

The increasing of distributed generators and high demand of customer service quality of recent years keep challenging the design and operation of electric power distribution systems. The future smart distribution grid is envisioned to be a large complex cyber-physical distribution system (CPDS), where physical grid components are monitored and controlled based on the interactions on the cyber space. As sensors and controllers, smart feeder remote terminal units (FRTUs) transfer necessary data to the control centre for situational awareness, and receive orders from the control centre for dynamic controlling. This study introduces an analytical FRTU deployment approach for the reliability improvement of integrated CPDSs. The FRTU deployment problem is modelled as a mixed-integer non-linear programming problem, which aims to minimise the total cost with the reliability index of average service available index as the constraint. Two kinds of distribution feeders (overhead and underground) are considered. The total cost includes the life cycle cost of FRTUs in addition to customer interruption cost. The proposed model can be solved by large-scale commercial solvers in an efficient manner. Test results of the RBTS-BUS4 distribution system and a China Southern Power Grid 62-bus distribution system validate the accuracy and effectiveness of the approach. Comparison with the genetic algorithm also shows its great efficiency.

Efficient integration of plug-in electric vehicles via reconfigurable microgrids

This paper investigates the viability of the reconfigurable microgrids (RMGs) in facilitating the integration of plug-in electric vehicles (PEVs). The reconfiguration ability of microgrids, which is enabled by the use of remotely controlled switches (RCSs), will support the high penetration of PEVs and renewable distributed generators (DGs) while reducing the total operation cost and potentially enhance microgrid reliability. The objective of the proposed optimal scheduling problem is to minimize the total cost of power supply by distributed energy resources (DERs) and upstream network energy exchange, battery degradation cost in PEVs, cost of switching during the reconfiguration, and expected customer interruption costs as a reliability index. To address the high level of the uncertainties in the problem, a scenario-based stochastic framework is devised to capture the uncertainties associated with the charging and discharging values of PEVs, number of PEVs in each fleet, time of the daily trips for PEVs, hourly load consumption, hourly output power of renewable DGs, and hourly market price. The satisfying performance and merits of the proposed model are examined on a test microgrid.

Modeling of integrated renewable energy system for electrification of a remote area in India

Over the years, renewable energy based power generation has proven to be a cost-effective solution in stand-alone applications in the regions where grid extension is difficult. The present study focused on the development of models for optimal sizing of integrated renewable energy (IRE) system to satisfy the energy needs in different load sectors of four different zones considered in Chamarajanagar district of Karnataka state in India. The objective of the study is to minimize the total cost of generation and cost of energy using genetic algorithm (GA) based approach. Considering optimization power factor (OPF) and expected energy not supplied (EENS), optimum system feasibility has been investigated. Based on the study, it has been found that IRES is able to provide a feasible solution between 1.0 and 0.8 OPF values. However, power deficit occurs at OPF values less than 0.8 and the proposed model becomes infeasible under such conditions. Customer interruption cost (CIC) and deficit energy (DE) for all zones were also computed to quantify the reliability of the systems.

A calculation method for a power user’s CIC under specific conditions in smart distribution grid

This paper presents a practical method for calculating a power user’s customer interruption costs (CIC) under specific conditions. This novel method has been developed, based on the CIC results predicted by Lawrence Berkeley National Laboratory (LBNL), so that the key factors, such as customer type, customer size, interruption occurrence time and interruption duration can be considered. As compared to the LBNL method, the method proposed here is easy to understand and easy to execute with an acceptable error. It lays a solid foundation for further investigation of distributed generators and demand response in assessing reliability value of smart distribution grid (SDG). The effectiveness of the proposed method is confirmed through the assessment of RBTS-Bus2.

Outage Management in Residential Demand Response Programs

This paper proposes a novel optimization based home load control (HLC) to manage the operation periods of responsive electrical appliances, determine several recommended operation periods for nonresponsive appliances, and schedule the charge/discharge cycling of plug-in hybrid electric vehicle (PHEV) considering various customer preferences. The customer preferences are in the format of payment cost, interruption cost, and different operational constraints. The projected algorithm is online, in which household appliances are initially scheduled based on the payment cost, and when the home load is interrupted, the scheduling will be updated to minimize customer interruption cost. Due to vehicle to home capability of PHEV, the home outage can be managed through solving the proposed optimization problem. Several realistic case studies are carried out to examine the performance of the suggested method. In addition, the impacts of common electricity tariffs on the HLC results are investigated. The results reveal that employing the proposed HLC program benefits not only the customers by reducing their payment and interruption costs, but also utility companies by decreasing the peak load of the aggregate load demand.

전력품질을 고려한 LVDC 배전계통의 신뢰도 분석

Recently, DC-based power system is being paid attention as the solution for energy efficiency. As the example, HVDC (High Voltage DC) transmission system is utilized in the real power system. On the other hand, researches on LVDC (Low Voltage DC) distribution system, which are including digital loads, are not enough. In this paper, reliability in LVDC distribution system is analyzed according to the specific characteristics such as the arrangement of DC/DC converters and the number of poles. Furthermore, power quality is also taken account of since LVDC distribution system includes multiple sensitive loads and electric power converters. In order to achieve this, LVDC distribution systems are modeled using ElectroMagnetic Transient Program (EMTP) and both the minimal cut-set method and Customer Interruption Cost (CIC) are used in the reliability analysis.

A multistage framework for reliability-based distribution expansion planning considering distributed generations by a self-adaptive global-based harmony search algorithm

In this paper, the authors present a new multistage framework for reliability-based Distribution Expansion Planning (DEP) in which expansion options are a reinforcement and/or installation of substations, feeders, and Distributed Generations (DGs). The proposed framework takes into account not only costs associated with investment, maintenance, and operation, but also expected customer interruption cost in the optimization as four problem objectives. At the same time, operational restrictions, Kirchhoff׳s laws, radial structure limitation, voltage limits, and capital expenditure budget restriction are considered as problem constraints. The proposed model is a non-convex optimization problem having a non-linear, mixed-integer nature. Hence, a hybrid Self-adaptive Global-based Harmony Search Algorithm (SGHSA) and Optimal Power Flow (OPF) were used and followed by a fuzzy satisfying method in order to obtain the final optimal solution. The SGHSA is a recently developed optimization algorithm which imitates the music improvisation process. In this process, the harmonists improvise their instrument pitches, searching for the perfect state of harmony. The planning methodology was demonstrated on the 27-node, 13.8-kV test system in order to demonstrate the feasibility and capability of the proposed model. Simulation results illustrated the sufficiency and profitableness of the newly developed framework, when compared with other methods.

Comparison of different models for estimating the residential sector customer interruption costs

Estimation of economic impacts of power interruptions in residential customers segment is a challenging and tedious task. The literature presents different methods to come up with sound calculations for these customer interruption costs. This paper makes use of a detailed customer survey study that was conducted in Finland and presents a comparison of five different models: WTA, WTP, direct worth approach, price elasticity approach and a new macroeconomic model. When doing the analysis a total of 1009 customers are divided into three sub-categories regarding the distinct characteristics of power consumptions: households, vacation houses and farm house customers.

초전도 한류기 적용시 배전계통의 신뢰도 비용 평가

In this paper, the effects of superconducting fault current limiter (SFCL) installed in power distribution system on reliability are evaluated and analyzed. The fault current will be decreased in power distribution system with SFCL because of the increased impedance of SFCL. The decreased fault current will improve the voltage drop of the bus of substation. The voltage drop is an important factor of power distribution system reliability. In this paper, improvement of reliability worth is analyzed when SFCLs are installed at the starting point in power distribution system. First, resistor-type SFCL model is used in PSCAD/EMTDC. Next, typical power distribution system is modeled. Finally, when the SFCLs with impedance 0.5 [Ω] are installed in feeder, power distribution system reliability is evaluated. Also, the improvement effect of reliability worth including the effect of voltage sag is analyzed using customer interruption cost according to whether or not SFCL is installed.

Improving reliability in an urban network

This paper describes various developments to improve reliability in urban power distribution networks. Actual implementation of different methods is addressed. The benefits are calculated according to the benefits achieved through regulatory incentives and through benefits obtained in asset management. The actual implementation in Helsinki presents both traditional and advanced smart grid implementations. The network supervision and control was previously limited to transmission and primary substation level only. Now with the implementation of both distribution automation and 100% coverage of smart meters, the entire grid from transmission to customer level is monitored and controlled. The impact of the chosen development methods on reliability indices in Helsinki is described. The future smart grid actions in Helsinki are also included.The main contribution of the paper is the holistic view on reliability improvement in urban distribution networks and the description of the actual implementations. The results show that with well planned and implemented actions the customer interruption costs and SAIDI in urban networks can be reduced by 50%.

정전비용 고려한 PV시스템의 배전계통 연계 우선순위 결정에 관한 연구

In this paper, when photovoltaic systems are connected to distribution system, most effective capacity and location of PV system are studied considering customer interruption costs of power distribution system. The reliability model of PV system considering the duration of sunshine, the model of time-varying load and Roy Billinton test system (bus2 model) are used. To simulate the effects of PV system, various cases are selected; (1) base case which is no connection of PV system to power distribution system when faults are occurred, (2) 3MW case which is 3[MW] connection of PV system (3) 4[MW] case, and (4) 20[MW] case which is 20[MW] connection of PV system to the bus of power distribution system. The capacity limit of connected PV system is settled to 14[MW] for all cases except case 4. The reliability and customer interruption costs for residential, general, industrial, and educational customer is evaluated.

Interruption costs of service sector electricity customers, a hybrid approach

Abstract A power outage brings in economic losses for both the customers and the utilities. Studying these unwanted events and making solid predictions about the outcomes of the interruptions has been an attractive area of interest for the researchers for the last couple of decades. By making use of a customer survey study conducted in Finland, this paper benefits from both the reported cost data collected from customers and from the analytical data that are available and then presents a new hybrid approach to estimate the customer interruption costs of service sector customer segment. Making use of Value Added information of the customers is a common practice for the cost normalization purposes. This paper verifies the approach by comparing the findings of the customer survey and the econometric model suggested here. This study is a unique source in terms of providing a reliable, easy to apply, and a straightforward model for calculating the economic impacts of power outages.

Multi-dimensional customer segmentation model for power system reliability-worth analysis

Accurate assessment of customer interruption costs is essential for making informed decisions in power system planning and operation. This paper presents a multi-dimensional customer segmentation model for reliability-worth analysis of power systems. The proposed model uses a hierarchical clustering technique to cluster electricity customers into customer segments of similar cost characteristics. Three customer parameters – economic size, economic activity and energy consumption are used in the proposed model. The proposed model is examined on two case studies from South Africa and Sweden, and results are compared to the conventional customer segmentation models. The effectiveness of the proposed model is determined based on the coefficient of variation of the final CIC estimates for different duration and time of occurrence of power interruptions. The results show a reduction in the dispersion of the final CIC estimates and thus allow CICs to be estimated from smaller survey samples.

Optimal Distribution Feeder Reconfiguration for Reliability Improvement Considering Uncertainty

This paper proposes a new method to improve the reliability of the distribution system using the reconfiguration strategy. In this regard, a new cost function is defined to include the cost of active power losses of the network and the customer interruption costs simultaneously. Also, in order to calculate the reliability indices of the load points, the reconfiguration technique is considered as a failure-rate reduction strategy. Regarding the reliability cost, the composite customer damage function is employed to find the customer interruption cost data. Meanwhile, a powerful stochastic framework based on a two- point estimate method is proposed to capture the uncertainty of random parameters. Also, a novel self-adaptive modification method based on the clonal selection algorithm is proposed as the optimization tool. The feasibility and satisfying performance of the proposed method are examined on the 69-bus IEEE test system.

Customer Interruption Cost in Smart Grids

Customers participating in demand response programs known as active customers provide significant flexibility in demand, thereby causing a meaningful reduction in customer interruption cost (CIC) during critical periods. This letter illustrates the impact on the amount of CIC of active customers' flexible demand realized by smart grid technologies. The focus of this letter is on residential electricity use. The study is applied to actual data from Kainuu, Finland.