An interrelation with power supply reliability, AT&C losses and energy efficiency
In today’s scenario, the key strategies for power distribution system reforms are ensuring reliability of supply, reducing AT&C losses, promoting sustainable energy usage and thereby leading to improving viability of distribution utilities. While distribution utility professionals focus on implementing the aforementioned strategies, however at times, the importance of power quality and its interrelationships with these ultimate objectives is not given due consideration. This article focuses on helping Indian utility professionals demystify the facts of PQ and considering PQ, since it is critical to achieve the desired results for distribution utilities.This also highlights the importance of considering PQ while designing and planning network improvements and expansions for power transmission and distribution utilities. With the increasing pace of modernisation, the existing electrical systems are unable to cater to the current demand of power quality. PQ escalations on the T&D systems are often complex, widespread and expensive to mitigate, hence utilities need to take PQ into serious consideration while planning network interventions.
The Indian electricity network is undergoing considerable change that is brought about by new technological advancement and the desire to make it smarter and more efficient. In today’s scenario, the key strategies for power distribution system reforms are ensuring reliability of supply, reducing AT&C losses and thereby leading to improving energy efficiency.
Reliability of supplyA major concern for Indian electrical distribution utility is maintaining “reliable power supply”. Reliability of supply implies that power is made available to the customer in right manner and without unplanned outage or interruptions disturbing normal life. Reliability and quality of supply were rarely considered as issues in the past and hence a little or no attention were paid towards it. However, modern economies are highly dependent on reliable and secure electricity services. In recent times the end customer has become more demanding and conscious about interruption free supply. Shortage of reliable supply impacts their normal life, thereby impacting economic and social growth.
Loss reductionPower distribution utilities in India are facing critical challenge of loss reduction so as to improve their financial performance and operate viably. Public distribution companies are facing huge burden of losses (` 2.4 lakh crore) and high average AT&C losses (28 per cent). Among this, the standard technical loss component is around 17 per cent in India, while remaining constitutes un-metered supply, pilferage and so forth. Loss reduction is core to the utilities and being driven by targets set by regulation. Distribution companies are exploring and investing in all areas, including network improvement, IT and business process improvement to meet their loss reduction targets.
Energy efficiencyEnergy efficiency emerged as a key policy priority in India’s energy sector since the enactment of Energy Conservation Act, 2001. The government estimates that the energy efficiency market in India has an investment potential of $10 billion and that improving energy efficiency could save up to 184 billion kilowatt-hours (kWh) of generated electricity.
Distribution transformer is one of the key equipment of power distribution network. Efficiency of the distribution transformers in various Indian power distribution utilities is very poor. Poor efficiency increases losses and reduces the quality and reliability of power supplied. Various state regulatory bodies have given directives to improve the efficiency of the DTs to improve the overall efficiency of power distribution network. Implementing or adopting energy efficiency measures decreases the overall energy demand and also peak demand, leading to higher reliability of supply. However, many devices that improve power reliability and quality, such as an inverter, a storage device, an uninterruptable power supply (UPS), or a dynamic voltage restorer (DVR) have possible negative impact on energy efficiency. Poor EE also affects the environment and the profitability of the utility consequently Indian economy.
PQ issues also commonly occur during power utilization at customer end. It impacts the electrical network components such as cables and transformers and creates excessive heating, overloading and early ageing of such components. Thus, although poor PQ and T&D losses are interrelated, systematic planned intervention can mitigate both risks. One of the key objectives of electricity network planning, given the ever increasing non-linear load environment, is to determine the upgrade and expansion requirements of the network so as to ensure supply of quality and reliable power to end consumers. PQ escalations on the T&D systems are often complex, wide spread and expensive to mitigate, hence having PQ as a design consideration in planning and management could be overall rewarding.
Key PQ issues and measures to improve performanceThe growing uses of electronic loads in the electrical networks have increased concerns about power quality. Due to the imbalance in the network performance quality indices across T&D systems like voltage regulation, supply and service have been affected. Some of the PQ disturbances in the network are caused due to:
Natural causesFaults or lightning strikes on transmission lines or distribution feedersFalling of trees or branches on feeders during stormy weather conditionsTransmission and sub-transmissionTransformer energisation or feeder capacitor switchingNetwork topography not updated leading to overloading or absence of ring mainAuto reclosing of breakers to tide over fault in networkEquipment failure because of poor O&MNon-linear loads on consumer sidePower electronic loads (UPS, ASD, converters, etc.), arc furnaces and induction heating systemsSwitching on or off of large loads.Immediate need for Indian regulators to measure and monitor PQ indicesCentral and state energy regulators are statutory bodies that govern reforms of power sector in India. They form policies regarding power management for utilities and customers. Maintaining good power quality is incumbent not only on the part of utilities but also customers. In India, however, utilities haven’t matured on the PQ concept and mostly the concept is mixed up with reliability of supply. It is high time now for regulators to make provision for PQ measurement and strict adherence by their respective licensees. Although all state regulators have code of supply in tariff regulations; however, it does not provide incentive or penalty mechanism related to quality of supply and hence utilities do not necessarily consider equally about continuity of power supply when compared with other priorities. Utilities could be compensated for the PQ investments made for laying up the infrastructure via ARR petitions.
With the ongoing regulatory, policy and tariff structural change in the Indian electricity industry (following the Electricity Act, 2003), the issue of PQ is poised to become a figure-of-merit amongst the competing distribution utilities. Improvement of PQ has a positive impact on sustained profitability of the distribution utility on the one hand and customer satisfaction on the other. Improved regulation, policies, standards and end-customer awareness and reinforcement will play key role in guiding market for optimum equilibria for good PQ environment.
ConclusionWith the increasing pace of modernisation, power consumption has been increasing exponentially. The existing electrical network systems are unable to cater to the current demand of power quality, grid reliability and efficiency. It is clear that in order to meet the increasing power requirements of the society, it is important that the utilities recognise the need to overcome PQ issues by upgrading the network with available technology interventions and practices. This can be achieved through better planning and designing of grids, constant vigilance, effective monitoring and good maintenance. A properly planned and maintained electrical system including that at distribution level will avoid multiple PQ issues, thereby balancing quality power supply on continuous basis – every hour of the day, every day of the year. Time is ripe that power distribution utilities take PQ into serious consideration while planning network interventions thus differentiating themselves in an increasingly open power market.
Authored by—Manas Kundu,Asia Power Quality Initiative (APQI),India Coordinator and Director (Energy Solutions),ICA India
Kunjan Bagdia,Senior Analyst Utilities, pManifold Business Solutions,APQI National Support Network (NSN) Partner
An interrelation with power supply reliability, AT&C losses and energy efficiency