Performance of 11KV distribution system

A Project Proposal On “Performance of 11KV distribution system and economic analysis” Key Words Distribution Power Quality Reliability Indices Improvements Economic factors Prepared By: Abdur Rahim Mallik Masters of Electrical Power Engineering Kathmandu University Advisory Teams: 1. Professor Arne T. Holen Department of Electrical Power Engineering Norwegian University of Science & Technology 2. Gautam Bajracharya Department of Electrical & Electronic Engineering Kathmandu University Project Proposal Project Proposal of Individual Research Work 1. Title: “Performance of 11KV distribution system and economic analysis” 2. Project Description: Energy is the basic necessity for the economic development of a country. There are many applications of electricity for which there are no alternative energy forms and , if the availability of quality supply for such uses are not assured all times, the way in which the businesses operate and the quality of life for most people will be adversely affected. It may cost for some customers to change their operations or equipment to reduce the impact of interruptions if their acceptance of a lower reliability level is reflected in reduced charges. All organizations involved in the electricity industry will wish to ensure that customers see electricity as an attractive form of energy. As the power industry moves into deregulation and customer power service requirements become more stringent, an increased emphasis is being placed on the quality of service being provided satisfactory service for most of the customer base, utilities are realizing the opportunity to market and sell higher "premium" grades of service to customers with equipment and processes sensitive to service variations and interruptions. In order to effectively market this service, as well as ensure the performance of the utility's power system in meeting customer requirements, the utility must assess the quality of service across its own distribution system. The distribution power quality and reliability of electricity supply is a national concern. Largest portion of the population of Bangladesh live in the remote rural areas. The government of Bangladesh has identified rural electrification as one of the major component of overall rural infrastructure which can expedite the economical growth, can create employment and improve the living standards. Bangladesh Rural Electrification Board (REB) is engaged in the rural electrification in Bangladesh. The objective of the Bangladesh Rural Electrification Board does not deviate far beyond the objectives of any power distribution organization in the world. One of the major objectives of REB is to deliver a quality and reliable electricity supply at least cost to the consumers. Quality refers to the voltage of the supply while reliability refers to the continuity of electricity. This project is a small exercise based on the requirement, the power quality and reliability of the Bangladesh Rural Electrification Board (REB) power distribution system. The main idea of this project is to identify the possible causes, which -1- Project Proposal affect the power quality and continuity of supply, and to analyze how it affects the customers, aiming to find out the way to minimize those effects locally as well as by means of modern technology. The scope of the project includes the following: • Distribution power quality ü Assessment of present operation performance of existing network under (REB). ü Voltage within tolerable upper & lower limit. ü Losses in the network. ü Active & reactive generation within planned or tolerable limit. ü Analysis of current situation through evaluation of power quality. ü Improving the performance of distribution systems to meet required targets (Voltage and power loss within tolerable limit) in selecting the most cost-effective technologies. • Reliability ü Study of failure mode experienced by the distribution system. ü Identification of influencing parameters in the reduction of the reliability of the system ü Analysis of current situation through evaluation of reliability. ü Cost analysis of power outages. 3. Background: System planning for electricity is essential to assure the customers demand by maintaining an acceptable limit of reliability, quality and safety at an economic price. The important considerations in the design and operation of a network are the determination of voltage drop, power loss and efficiency of transmission. Reliability and quality of electric power is one of the most discussed topics in the power industry to-day. There is an increasing worldwide trend of T&D companies tracking service quality and reliability performance indicators. Electric utilities in Bangladesh are facing the pressure of reducing costs and improving the quality and reliability of supply. Though the generation and transmission systems have seen considerable technical development and capital investment, the distribution systems have been neglected and have suffered due to poor operating efficiencies leading to financial losses and cynical customer perception. The distribution systems have suffered mainly from the following maladies: • • • • • Unbalanced Load Flow Poor voltage regulation High level of Technical (Peak power/Energy losses) Conductor Heati ng / Equipment Damages. Very high unaccounted interruption & poor reliability For distribution system, performance is indicated by the following terms : -2- Project Proposal Power Quality: Even the standards themselves are outdated, based on the Electricity Rules in Bangladesh the allowable ranges of: § Voltage- Voltage for low-voltage (retail) consumers is allowed to deviate by 8% § Frequency- The frequency is allowed to deviate by 3%. § Power loss- The distribution power loss is allowed to deviate by 10%. Reliability: § Reliability—The degree of performance of the elements of an electric system that results in electricity being delivered to customers within accepted standards and in the desired amount, measured by the frequency, duration and magnitude of adverse effects on the electric supply and by considering two basic and functional aspects of the electric system: adequacy and security. Reliability indices—Service performance indicators which measure the frequency, duration and magnitude of customer interruptions, excluding outages associated with major events. Adequacy—The ability of the electric system to supply the aggregate electrical demand and energy requirements of the customers from various electric generation suppliers at all times, taking into account scheduled and reasonably expected unscheduled outages of system elements. Security—It relates to the ability of the power system to respond to disturbances arising from equipment within either the bulk power system or, to the local distribution system and so maintain supply at an acceptable frequency and voltage. § § § Traditional measures of reliability used by electricity distributors include: § SAIDI— System Average Interruption Duration Index (SAIDI) is the average interruption duration per customer served per year. § SAIFI— System Average Interruption Frequency Index (SAIFI) is the average number of interruptions per customer served per year. § CAIDI— Customer Average Interruption Duration Index (CAIDI) is the average interruption duration for customers interrupted during a year Utilities in Bangladesh do not publish standard performance statistics -SAIDI, SAIFI & CAIDI as they would be an order or two of magnitude behind acceptable norms. Improving the performance of distribution systems to meet required targets is a matter of selecting the most cost-effective technologies and operating practices. The distribution systems tend to be very extensive with a long life span for conductors and plant. It is not sufficient to analyze how a particular portion of the network may be modified to improve its performance today: it is a matter of determining what would be the optimal solution when allowance has also to be made for the uncertainties in the prediction of the future scenario of customer demand. It is valuable to investigate long -term solutions especially so when the -3- Project Proposal implementation of the solutions will also entail decisions involving large-scale investments. The project deals with the performance of 11 KV electrical networks under Bangladesh Rural Electrification Board (REB). One of the major challenges facing utility is to measure and establish benchmark levels for power quality to a national basis. In these circumstances, the initial task is the development of a consistent framework based on historical data from collaborating utility and focus to minimize risk and uncertainty in managing service quality & reliability. It will be interesting because it is required to consider present load flow study, explore future power system scenario and employ appropriate methods of voltage & power control and on an economic basis to assure a very high degree of system reliability. 4. Objectives of the project: The project consists of two fundamental research areas that address a range of topics related to the power quality and reliability performance of distribution systems. They will provide the information and tools needed to address the design and operation of distribution systems as the needs of customers continue to evolve and new technologies become available to improve system performance. Critical areas of research are described below. • • Distribution Power Quality (DPQ) and Reliability Projects identify traditional and technology-based solutions for managing and improving distribution power quality and reliability. This area assesses the PQ aspect of distribution operation practices and identifies tools and methods that can be cost-effectively utilized for DPQ and reliability improvement. The main objective of the project is to analyze the distribution power quality and reliability to examine the state of the REB power distribution system and to study the ways and means of improving the DPQ and reliability at an economic basis. So, the study of the projects is limited to: o o o o o o Voltage drop study Technical loss study Reliability analysis Voltage regulation and loss control practices Reliability management practices Economic factors -4- Project Proposal So, Performance analysis of 11KV distribution system and most economic voltage & power control and reliability enhancement considering all financial and technical aspect and general guidelines to determine the most economical solution are the main objectives of the research project. 5. Methodology: Based on the objectives, the following work shall carryout the following tasks: 1. i) ii) iii) iv) v) Collection of data for case study regarding the following: Visit the proposed site(Any 33/11 KV substation under Dhaka / Tangail Rural electric Co-operative). Status of existing 33/11 KV substation. Single line diagram of the network including type of line of each section, length of line section, conductor size etc. Size, Losses and Loading of different 11/0.4 KV distribution transformers connected to the network. Reliability data shall be collected for 1 year such as: Monthly interruptions & effected consumer, Duration of interruption, Causes of interruption. 2. Distribution power quality: i) Perform load flow analysis to examine the state of the system. ii) Load growth studies for 20 years (up to year 2025). iii) Perform load flow analysis considering future load growth. iv) Improving the perfo rmance of distribution systems to meet required targets (Voltage and power loss within tolerable limit) in selecting the most cost-effective technologies. v) Optimal capacitor placement and sizing to minimize losses and / or improve voltage profile and reconductoring the system. vi) Design detail compensation alternatives. vii) Detail costing of different compensation alternatives. viii) Optimization of different compensation alternatives. ix) Perform load flow analysis for the optimized option. x) Recommendation the best alternatives considering all financial and technical aspect. xi) Study shall be carried out in four steps (for each five years) and recommendations shall be made for each step. Reliability study: Study failure modes experienced by distribution system Identification of influencing parameters in the reduction of the reliability of the system. Analysis of current situation through evaluation of reliability. Cost analysis of power outages. 3. i. ii. iii. iv. -5- Project Proposal 4. General guidelines to improve the performance of distribution systems to meet required targets in selecting the most cost-effective technologies and operating practices. 6. Tools: Load flow analysis shall be carried out with the help of NETBAS program. 7. Outcome: The outcome shall be in the form of a report regarding Line length of 11 KV system, Loading of transformer located at different points, Monthly interruptions & effected consumer, Duration of interruption, Causes of interruption, improving the performance of distribution systems to meet required targets in selecting the most cost-effective technologies, Detail costing of optimization, recommended the best alternative for satisfactory performance of the system, Load flow analysis and General guidelines to improve the performance of distribution systems to meet required targets in selecting the most cost-effective technologies and operating practices. 8. Work Plan: Duration of the project shall be six months including site visiting, data collection, analyze the data and finalize the report. July – August : Site visit & Data collection September – October : Load flow analysis October - November : Optimization of load flow September – October : Reliability analysis September – December : Report writing Description of July,05 work Site visit & data collection Load flow analysis Load flow optimization Reliability analysis Report writing Aug.,05 Sept.,05 Oct.,05 Nov.,05 Dec.,05 -6-