Planning Of Power Distribution Systems Research Articles

A novel approach for techno-economic reliability oriented planning and assessment of droop-control technique for DG allocation in islanded power distribution systems

An effective planning strategy for deploying distributed generators (DGs) provides economic advantages through optimal net present cost (NPC), improved technical performance, enhanced voltage profile, and minimized line losses. Nevertheless, technical performance varies based on the control techniques implemented for power regulation in DGs. Therefore, it is crucial to incorporate DG control strategies for efficient and robust power distribution system planning. This study discusses a novel approach for techno-economic reliability-oriented planning in an IEEE-33 bus droop-controlled islanded power distribution system. The presented study evaluates the influence of incorporating control techniques on the sizing and placement of DGs along with the technical, economic and reliability parameters. The problem formulated for optimal DG allocation aims to achieve the optimum NPC, minimize line losses, improve system reliability, and ensure voltage and frequency agreement with IEEE std 1547™-2018. The problem formulation is structured as a multi-objective problem and is solved using the particle swarm optimization (PSO) technique to achieve optimal bus location and size for DG installation. The study reveals that considering the control strategy helps in achieving efficient and reliable planning structure.

Optimal planning of power distribution system employing electric vehicle charging stations and distributed generators using metaheuristic algorithm

Optimal planning of power distribution system employing electric vehicle charging stations and distributed generators using metaheuristic algorithm

A Novel Hybrid Algorithm based Planning of Power Distribution System Considering Emission Pollutants

This study investigates a new hybrid algorithm, which is a combination of an enhanced elephant herding algorithm (EEHA) and the Jaya algorithm (JA). This hybrid enhanced elephant herding jaya algorithm (EEHJA) controls the searching properly from global exploration to local exploitation to obtain a near-global optimum. The suggested algorithm is employed to optimise the reconfiguration and integration of renewable distributed generations (DGs) taking the novel type of buses P, PQV. The voltage at the PQV bus is regulated by the P bus with a reactive power assist (RPA). Sensitivity factors based on curtailment in active power loss (APL) and enhancement in bus voltages are proposed to obtain optimal DG locations. During reconfiguring network topology (RNT), a smart graph theory technique based on the spanning tree concept authenticates the topological restrictions. The proposed algorithm is applied to optimise the RPA at the P bus, solar photovoltaic DGs ratings, and optimal RNT of the power distribution system (PDS) to minimise the APL. The placement of solar photovoltaic DGs has been studied in two approaches namely, sequential and non-sequential allotment. Further, different cases are studied based on optimum RNT including and excluding DGs, and RPA by the suggested methodology on 33 and 69 bus radial PDS. Moreover, the pollutant emissions like CO2, SO2, and NOX in the environment due to traditional energy sources are further reduced. The adequacy of this novel methodology is verified with recently developed meta-heuristic algorithms and the obtained numerical results demonstrate the validity and its effectiveness.

Comprehensive building clustering as an abstraction method for planning of power distribution systems

Comprehensive building clustering as an abstraction method for planning of power distribution systems

Methodology for integrating flexibility into realistic large-scale distribution network planning using Tabu search

A successful energy transition will be firmly based on the effective integration of distributed energy resources and on the integration of new flexibility providers into the energy system. To make this possible, a deep transformation in the design, operation and planning of power distribution systems is required. Currently, a lack of comprehensive planning tools capable of supporting operators in their investment plan options exists. As a result, reinforcements of conventional grid assets are common solutions put in place. This paper proposes a methodology to obtain cost-optimal distribution network expansion plans, by modelling a single-stage distribution network planning tool, using conventional assets as well as flexibility contracting from demand response. A Tabu Search metaheuristic has been implemented in order to solve the optimization problem. A case study based on a realistic large-scale city network model is presented, for a planning horizon of ten years with significant load growth due to electromobility penetration. Results show that, in the case study analysed, the use of load flexibility in combination with conventional reinforcements can reduce the total expansion network cost by about 7.5 %. Furthermore, a sensitivity analysis on the cost of flexibility contracting is undertaken. Remarkably, the methodology presented generalises to further alternative solutions by providing a straightforward financial benchmark between the latter and conventional grid expansion.

A Practical Feeder Planning Model for Urban Distribution System

There is a significant gap between academic research and practical application for power distribution system planning (PDSP). For most of the existing PDSP models in academic research, cost is used as the objective function, and the most common constraints are power flow equality constraints, bus voltage or voltage drop limits, substation and feeder capacity limits, etc. Although various advanced models and methods have been proposed, they are rarely used in real distribution system companies. This paper proposes a new feeder planning model for the urban distribution network considering various practical requirements. According to field investigation, “supply electricity to loads using nearby power sources” is used as the objective, and it is analytically expressed by load moment. Block loads, practical street layout, meshed network configuration, connection mode of feeders, non-crossing requirement of feeders, power supply radius, etc., are all respected and embedded in the model. The proposed model is recast as a mixed integer linear programming (MILP) problem, and it can be solved by the state-of-art commercial solver. The effectiveness and validity of the proposed model are illustrated on a 9-block test system and a real 22-block district distribution system.

Replacement of LVDS to HVDS for Reduction in Distribution Losses, Improvement in Voltage Profiles and Economic Analysis for National Saving

Introduction: Rural electrification in India is planned with high-capacity distribution transformers which supply the isolated location loads of various categories like agricultural, household, small business, etc. This distribution system planning with non-optimal distribution transformers leads to poor voltage profiles and high power losses in the distribution network. This paper presents that a High-Voltage Distribution System (HVDS) is more suitable than a Low- Voltage Distribution System (LVDS). Methods: A model is developed to evaluate the technical losses, voltage profiles, and optimal payback period of the investments for the planned HVDS network. The replacement of LVDS with HVDS is achieved by replacing high-capacity distribution transformers with small-capacity at optimal locations. Results: The results of this study are validated on the real 11kV agricultural feeder of the Narshinghpur District of Madhya Pradesh, India. Conclusion: The results demonstrate improvement in voltage profiles, low power losses, and optimal payback period for the proposed problem. The obtained results proved that the replacement of LVDS with HVDS would be more beneficial for rural electric power distribution system planning.

Special Issue: Control, Optimization and Planning of Power Distribution Systems

The use of renewable energy sources is moving the generation from the top to the bottom of power systems, where traditionally only loads existed [...]

A Framework for Reliability Assessment in Expansion Planning of Power Distribution Systems

This article proposes a framework that uses analytical assessment of reliability to guide the expansion planning of power distribution systems (PDS) considering reliability criteria. The framework allows the estimation of reliability indices with and without the execution of expansion projects, thus supporting the decision-making process on investments in expansion projects. In the analytical assessment of reliability, failure rates of zones and restoration times are calculated from past data of interruptions in the primary distribution network. In addition, the estimated reliability indices are adjusted to historical values through failure rates proportionate to the length of each zone. To test and validate the proposed framework, it was applied to the distribution network at bus 5 of the Roy Billinton Test System (RBTS) and also to a real distribution feeder located in Brazil. The results indicated that the proposed framework can help define the most attractive investments leading to improvements in reliability indices and reduction in unsupplied energy. The estimation of reliability indices and energy not supplied, considered the following expansion alternatives: (i) the installation of normally-closed sectionalizing switches, (ii) the installation of normally-open switches with interconnection to adjacent feeders, (iii) the automation of switches, and (iv) the reconductoring of zones of the primary distribution network. Nevertheless, the proposed framework allows the inclusion of other expansion alternatives. Finally, the proposed framework proved to be handy and useful for real-life applications.

Expansion Planning of Power Distribution Systems Considering Reliability: A Comprehensive Review

One of the big concerns when planning the expansion of power distribution systems (PDS) is reliability. This is defined as the ability to continuously meet the load demand of consumers in terms of quantity and quality. In a scenario in which consumers increasingly demand high supply quality, including few interruptions and continuity, it becomes essential to consider reliability indices in models used to plan PDS. The inclusion of reliability in optimization models is a challenge, given the need to estimate failure rates for the network and devices. Such failure rates depend on the specific characteristics of a feeder. In this context, this paper discusses the main reliability indices, followed by a comprehensive survey of the methods and models used to solve the optimal expansion planning of PDS considering reliability criteria. Emphasis is also placed on comparing the main features and contributions of each article, aiming to provide a handy resource for researchers. The comparison includes the decision variables and reliability indices considered in each reviewed article, which can be used as a guide to applying the most suitable method according to the requisites of the system. In addition, each paper is classified according to the optimization method, objective type (single or multiobjective), and the number of stages. Finally, we discuss future research trends concerning the inclusion of reliability in PDS expansion planning.

Accuracy of load and generation forecasts for the operational planning of power distribution systems

Operational planning in future power distribution systems will depend on load and generation forecasts as decisions and analyses will be performed in an increasingly coordinated manner at lead times. Forecasts on distribution level are significantly less accurate than on transmission level. The evaluation of forecast accuracy is therefore necessary to ensure system security. In this paper, forecast errors of wind power, photovoltaic power and load are evaluated for a medium-voltage grid region. Various influencing variables on forecast accuracy are examined. The evaluations show that forecasts in particular become worse for low aggregation levels and higher forecast horizons. In addition, the forecast error depends on characteristics such as the time of day or the magnitude of the forecast. For a secure system operation, forecast errors as well as their dependencies should be taken into account. Operational decisions should be made within the shortest possible lead time.

Multiobjective Approach for Medium- and Low-Voltage Planning of Power Distribution Systems Considering Renewable Energy and Robustness

In this paper, a multiobjective approach to carry out the planning of medium-voltage (MV) and low-voltage (LV) distribution systems, considering renewable energy sources (RES) and robustness, is proposed. Due to the uncertainties associated with RES and demand, the proposed planning methodology takes into account a robust planning index (RPI). This RPI allows us to evaluate the robustness estimation associated with each planning solution. The objective function in the mathematical model considers the costs of investment and operation and the robustness of the planning proposals. Due to the computational complexity of this problem, which is difficult to solve by means of classical optimization techniques, MV/LV planning is solved by a decomposition search and a general variable neighborhood search (GVNS) algorithm. To demonstrate the efficiency and robustness of this methodology, tests are performed in an integrated distribution system with 50 MV nodes and 410 LV nodes. Our numerical results show that the proposed methodology makes it possible to minimize costs and improve robustness levels in distribution system planning.

A comprehensive MILP model for the expansion planning of power distribution systems – Part I: Problem formulation

This first part of the paper presents a comprehensive mixed integer linear programming model which can be applied to the expansion planning of power distribution systems. The model describes the problem of allocation of voltage regulators and capacitors including reconductoring. In addition, it determines the optimal position of the taps of voltage regulators and transformers. Due to its flexibility, the model provides a solution that simultaneously coordinates the operation of distributed generation sources with all volt/var control devices. We propose a linearized model to obtain the steady-state operating point of distribution systems, whereas the optimization problem is represented as a mixed integer linear programming model. As a further advantage, this approach guarantees the convergence to optimality using classical optimization techniques. Based on typical examples, the second part of the paper demonstrates the validity and efficiency of the model described here.

A comprehensive MILP model for the expansion planning of power distribution systems – Part II: Numerical results

This second part of the paper presents and discuss results from the implementation of the MILP model presented in Part I. This comprehensive model is intended for the expansion planning of power distribution systems. The results were obtained using the programming language OPL and the minimization problem was solved using the CPLEX solver. We applied the model to three known systems, with 23, 54 and 69 buses, and also to a system with 276 buses containing real data, to illustrate potential uses and advantages of the proposed formulation. For the sake of validation, a comparison was carried out between the results obtained with the linearized model and the results obtained through a conventional load flow, showing the accuracy and efficiency of the model. Furthermore, the results obtained for the 54-bus system were compared with equivalent results obtained with another MILP model.

MOSOA-Based Multiobjective Design of Power Distribution Systems

This paper presents a multiobjective (MO) evolutionary algorithm for solving a contingency-based MO design of power distribution system (PDS) by extending the original and powerful metaheuristic approach based on a MO seeker optimization algorithm (MOSOA). Normally, reliability is a major concern in existing PDS planning, as estimation of failure rates and fault repair duration of the feeder branches is difficult in practice. The proposed planning methodology uses a contingency-load-loss index for reliability evaluation, which is independent of the failure rate and fault repair duration of the feeder branches. This planning strategy includes distribution automation devices such as automatic reclosers (RAs) to enhance the reliability and efficiency of the distribution system. The proposed algorithm generates a set of nondominated solutions by the simultaneous optimization of two conflicting objectives (economic cost and overall system reliability) using Pareto-optimality-based tradeoff analysis. The performance of the proposed approach is assessed and illustrated on a 54-bus distribution system, considering real-time design practices and meeting the additional requirements that the designer imposes. The information gained from the Pareto-optimal solution is shown to be useful for final decision making of a PDS. Furthermore, a qualitative comparison is made with the nondominated sorting genetic algorithm-II, showing the efficacy of the proposed planning approach.

The Effect of Distributed Generation Type and Location Constraints on the Solution of the Allocation Algorithm

Modern planning of power distribution systems faces significant changes over the last few decades due to the massive introduction of distributed generation units. In this paper the authors discuss the inclusion of location constraints for optimal allocation of DG units. The goal function will be the minimization of cumulative average daily active power losses. Four types of DG units will be considered; a solar park, a wind farm, a power station that does not depend on an intermittent primary energy source and a small hydro unit. Each DG unit and network load will be modeled with its own characteristic average daily power production or consumption curve. The network load will consist of residential and industrial consumers. The problem will be solved using genetic algorithm and realized in Matlab programming environment.

负荷同时率在中低压配网改造中的分析与应用

作为电力市场分析的一项基础工作，负荷特性的调研和分析对于电力企业的经营、规划和发展越来越重要。负荷同时率是电力负荷的重要特征之一，也是配电系统改造中的一个基础参数。受运行数据采集方式的限制，以往分析计算得到的负荷同时率与实际值相差较大。电力系统计算机监控系统的普及，为提高负荷实测数据的同时性和准确性提供了有力条件。本文分析了影响配电网负荷同时率的因素，然后提出了配电网系统负荷同时率的实测计算方法，并考虑负荷同时率这一因素来分析馈线装接容量的控制方法。佛山中低压配电网的应用表明本文方法具有实用性。 As the basic work of power market analysis, research and analysis of load characteristics is becoming more and more important for the business development of utilities. Load simultaneity factor is one of the important features of power load, which is also a basic parameter of in power distribution system planning. Due to the restrictions of operating data acquisition, the load simultaneity factor in traditional analyzing and calculating calculation of was always far from the actual value. The popularization of computer monitoring systems in power systems has provided powerful conditions for improving the equivalence and the accuracy of load measured data. Thus, this paper analyzes the factors affecting the load simultaneity of distribution network firstly, and then puts forward the calculation method of the actual measured load simultaneity of distribution systems. Moreover, the method for analyzing and controlling the feeder loading capacity considering influence of the load simultaneity factor is presented too. The applications in the medium and low voltage distribution network in Foshan show that the method is practical.

Power Distribution System Planning Evaluation by a Fuzzy Multi-Criteria Group Decision Support System

The evaluation of solutions is an important phase in power distribution system planning (PDSP) which allows issues such as quality of supply, cost, social service and environmental implications to be considered and usually involves the judgments of a group of experts. The planning problem is thus suitable for the multi-criteria group decision-making (MCGDM) method. The evaluation process and evaluation criteria often involve uncertainties incorporated in quantitative analysis with crisp values and qualitative judgments with linguistic terms; therefore, fuzzy sets techniques are applied in this study. This paper proposes a fuzzy multi-criteria group decision-making (FMCGDM) method for PDSP evaluation and applies a fuzzy multi-criteria group decision support system (FMCGDSS) to support the evaluation task. We introduce a PDSP evaluation model, which has evaluation criteria within three levels, based on the characteristics of a power distribution system. A case-based example is performed on a test distribution network and demonstrates how all the problems in a PDSP evaluation are addressed using FMCGDSS. The results are acceptable to expert evaluators.

Long-range planning of power distribution systems: Secondary networks

This paper presents an optimization-based methodology for low-voltage distribution network design. The system is composed of three mathematical models: distribution transformer location, secondary feeder routing and transformer sizing, and primary-transformer interconnection. A heuristic solution approach calculates the actual total installation cost for an increasing number of transformers until the minimum cost solution that meets the forecast demand and problem constraints is attained. Results are compared with those obtained by using an empirical approach.

Long-range planning of power distribution systems: primary networks

This paper focuses on the expansion planning of power distribution systems. An optimization model that simultaneously considers substation location and sizing, primary feeder routing and reconductoring is used to design the expansion plans. The model considers the fixed and variable costs for all new elements and also for the existing ones when expansion is taken into account. The objective function seeks to minimize the total annualized expansion cost that includes the cost of losses modeled as a quadratic function. An efficient implicit enumeration algorithm combined with several heuristic procedures allows large expansion problems to be solved in a very reasonable time using microcomputers. The radiality constraints are obtained by applying heuristics that deal with the true expansion costs. The voltage drop constraints are checked in the final radial solution and corrective actions are performed if they are not satisfied.