S.A. Khaparde

• Indian Institute of Technology Bombay

With the increasing penetration of primarily inertia-less distributed energy resources, allowable delay in the fast frequency reserve provision to ensure marginal stability condition can become comparable with the requisite dead-time for fast-switching in a radial power distribution system (PDS) connected to the transmission system. Consequently, t...

Voltage sag mitigation utilizing dynamic voltage restorers (DVRs) is usually classified as a common-pool resource (CPR) good. However, the ability of the DVRs in improving voltage sag performance of the downstream customers provides the ability to exclude the non-contributors selectively. Therefore, unlike traditional CPR good, the DVR allocation p...

With the reduction in available inertial reserve and increasing penetration of inverter-interfaced generators, traditional allowable delay in the provision of the primary frequency reserve will threaten the security of the future grid. However, droop control with fast-enough inertia-less generators can limit the post-contingency frequency excursion...

In an open system, system resources are managed by the contributors themselves. Because, participation needs to be voluntary, proper communication is essential among the participants, while contributors' true utility requirement will be unmonitored. In the discussed common pool resource (CPR), the non-excludable component of the resource is require...

This paper presents computation of swing modes of a large power system that could be significantly affected by power swing damping controllers in FACTS or HVDC devices at a given location. Modal controllability is a suitable measure to isolate these modes for analysis. Computation of the controllable swing mode spectrum is useful, especially in sit...

CIM is widely adopted by many utilities since it offers interoperability through standard information models. Storing, processing, retrieving and providing concurrent access of the large power network models to the various power system applications in CIM framework are the current challenges faced by utility operators. As the power network models r...

In this paper, a ‘two-stage’ deterministic algorithm for efficient transmission expansion planning with renewable energy (RE) resources under the assumption that existing conventional generators provide the reserve to mitigate RE generation forecast error has been proposed. Zero-RE penetration has been considered as a ‘reference scenario’, as well...

Deregulation of the power industry and the shifting of investment into different types of generation capacity such as distributed energy resources have complicated today's power grid and pushed it nearer to its operating limits. As a consequence, operations of the power grid have become significantly more dependent on complex computer-based, analyt...

In India, uniform price was assigned to renewable energy certificate (REC) irrespective of renewable energy (RE) type, technology, and location. Moreover REC price bands are higher than existing preferential tariff. There are distinct renewable purchase obligations (RPOs) specified for various RE types, whereas there is lack of efficient tools to c...

Perform Achieve Trade (PAT) is a market-based incentive mechanism to promote energy efficiency. The purpose of this work is to address the challenges inherent to inconsistent representation of business processes, and interoperability issues in PAT like cap-and-trade mechanisms especially when scaled. Studies by various agencies have highlighted tha...

Common information model (CIM) in vogue represents transmission and distribution components, and market operations in the perspective of electrical system, as unified modeling language (UML) objects. UML is object centric. CIM can offer interoperability and facilitate model exchange for large systems and is being adopted by many utilities. However,...

Although common information model (CIM) standard has been already a recognized power system domain standard, utilities are facing difficulties in the process of upgrading their software systems on CIM framework. Significant challenges faced by utilities are due to various issues such as legacy of distinct names given to the same power system resour...

Many utilities and control centers are now implementing the new interoperability CIM standards since it facilitates model and data exchange. In accordance with application use cases, application profiles are projected out of standard CIM primitives and relationships. The CIM standard allows high granularity customization for designing CIM profiles...

Future grid evolutions promise to promote the interoperability in the consumer domain. CIM (mainly IEC61970 and IEC61968) is an established standard in the industry to enable the interoperable data exchanges at the upstream levels like generation, transmission and distribution, while the Green Button standards (OpenADE, NAESB ESPI, NIST SGIP-PAP 20...

New generation of future power system control centers need a paradigm shift in their utility IT operations, coordinated use of applications and the architectural designs to meet new challenges. However, literature on comprehensive architectural design and implementation towards this direction is scarce. In this paper, an architecture design and imp...

Government of India has laid the foundation of national solar mission to establish the country as a global leader in solar energy. Tariff is a crucial factor for penetration of the solar energy across the country. This paper presents operational aspects & prevailing tariff structure of combined solar photovoltaic and battery (PV-Battery) energy sys...

Conventional power system graphic applications use absolute coordinates approach, in which the objects are positioned with respect to a common origin. This can result in problems of re-adjustment and re-alignment in the network and substation diagrams when editing or merging the graphics. This paper introduces the notion of layouts and proposes a g...

Establishment of the interoperable applications at the electricity generation, transmission, distribution, and market domains is almost accomplished through various standardization activities. At this juncture, advent of the smart grids has opened the new avenues like the consumer domain for the standardization activities, and down the time-line th...

Renewable Purchase Obligation (RPO) regime in India started in 2011 with the announcement of benchmark RPO (BRPO) of states for the Financial Year (FY) 2011 by respective State Electricity Regulatory Commissions (SERC), to promote Renewable Energy (RE). The report submitted to Forum of Regulators (FoR) in this regard has recommended uniform rate of...

Govt. of India has come up with renewable energy (RE) promotional policies and regulations to tap the abundant renewable energy sources in the country for energy security and to reduce the dependance on fossil fuels. Subsequent to the enactment of the Electricity Act 2003, Renewable purchase obligation (RPO) became mandatory on power distribution c...

The primary objective of this paper is to design a security-constrained locational marginal pricing framework with specific emphasis on creating clear incentive for the demand side to make participation in serving the reserve option. Both the contingency forms, such as line outage and generator outage, are taken into account. The reserve services f...

For the assessment of voltage instability which comprises the detection of voltage instability and identification of critical buses, two indices namely, system wide Qtax, and bus-specific qtax, are proposed. The Qtax, based on the sensitivity of the reactive power injections to the loading in the system provides early detection of impending voltage...

The objective of this paper is to suggest a robust optimal power flow (OPF) framework to perform locational marginal pricing under the scarcity of reactive power. The classical OPF models employed for market clearing either assume infinite reactive power support or make a fully independent representation of the reactive power load. In contrast, a p...

Although the standards-based systems integration of utility software applications using the domain data standard common information model (CIM) exists, many utilities are facing difficulties in managing of data exchanges among software application systems due to lack of standard oriented database management systems. The standard oriented database c...

Though the new wind turbine generator (WTG) technology offers fault ride-through capability (FRT), many systems still consist of old induction generators. These induction generators typically have the problems of voltage limit violations which result in undesirable tripping. Their response to abnormal conditions like faults has to be studied for pr...

Short term open access (STOA) transactions are one of the important mechanisms for exchange of power on Indian national grid. Currently, STOA is operated by five regional load despatch centers, leading to differences in representation of STOA transaction information. This paper presents the modeling of STOA using common information model (CIM). Use...

Common Information Model (CIM) has been identified as the information exchange platform for Distribution Management. Distribution utilities in India perform multiple functions of varied nature to meet equivalently myriad challenges, in many ways unique to them. This paper discusses two of them, namely, load shedding & restoration and power purchase...

Exchange of event information among multiple interconnected power system operators has become imperative for integrated and secure operation of the system. Considerable literature is reported on the standardization of power system data, while limited work has been done on the standardization of events. In this paper, we define a high level event on...

Demand response (DR) has an important role to play in the electricity market for maintaining the balance between supply and demand by introducing load flexibility instead of only adjusting generation levels, at almost all operational time scales. There are many players in the market who benefit from DR, like the TSO, DSOs, retailers and end-custome...

The objective of this work is to design a suitable rule for the energy reference selection in the AC optimal power flow (ACOPF)-based locational marginal price (LMP) calculation. In the case of the ACOPF model, the congestion component of the LMP vector exhibits strong dependence on the energy reference. This in turn makes the hourly values of fina...

That event driven architecture (EDA) will compliment the data driven systems in future is evident from the current literature. In this paper, the use of event driven architecture (EDA) as a platform for supporting event ori- ented applications in power control centers is presented. EDA operates on the semantics of events and event patterns, which a...

This paper presents novel approaches for Transmission System Expansion Planning (TSEP) Studies which are tested on practical Indian power system. Due to the practical applicability for large systems to obtain a better solution, a meta-heuristic optimization method, DEMO^NS-II has been chosen as a tool for carrying out the multi-objective...

In terms of scope and granularity of data, two kinds of connectivity models are broadly in vogue for representing power network data, namely, node-breaker model and bus-branch model. This paper examines both the connectivity models from the perspective of common information model (CIM). Although CIM is primarily designed for most detailed node-brea...

India is moving on the path of rapid growth and restructuring with ever changing regulatory environment. There is a direct impact of this changing structure of power sector on system operation. New roles and responsibilities have to be taken up involving co-ordination with various external utilities. Standards based integration of systems and appli...

The first decade of the twenty first century saw the Indian electricity sector witnessing fast paced structural changes. Regulatory intervention and policy thrusts have been the significant drivers of this change. The utilities have also adapted to these changes. This paper outlines the various milestones crossed in the first decade and the newer c...

India is a highly diverse country with regard to its electrification status, covering all from well developed cities to rural areas without access to electricity. It has identified renewable energy sources as the long-term solution for future energy and progressing in the direction of electrifying the unreachable pockets. In this context, paper acc...

That the new generation power system control centers need a paradigm shift in their architectural design to meet new challenges, is an established conclusion of many researchers. However, literature on comprehensive architectural design towards this direction is scarce. In this paper, an information architecture design is proposed for the power sys...

Transmission power flows are dependent on physical laws. Transmission system expansion planning (TSEP) of a transmission utility in the deregulated environment becomes complex. It has been identified that utilities mainly perform planning to serve the needs of their own customers within a defined service territory. However, there needs to be a coor...

The Electricity Act, 2003 has de-licensed generation and provided enabling provisions for setting up of generating plants by the independent power producers (IPPs). Till the X^th plan period (2002-2007), the private sector did not play a significant role. However, during the XI^th (2007-2012) and XII^th (2012-2017) pla...

SmartGrids were introduced to make the grid operation smarter and intelligent. SmartGrid operations, upon appropriate deployment can open up new avenues and opportunities with significant financial implications. SmartGrids can continue towards enhancement of power market. The current status of the power market as well as initiations of SmartGrids i...

The MicroGrid concept using renewable energy sources is a building block towards the future energy networks for long-term viable solution of energy needs. The focus of the paper is centred around the encountered and foreseen issues, enabling technologies and economics for encouraging the deployment of MicroGrids in India. This paper presents state-...

Modern day power systems in the restructured environment have grown to a level of complexity that the use of automation has become imperative for secure operation and control. The volume of significant events that occur in a multi-area interconnected power system has become enormous to an extent that system operators need intelligent systems to sup...

In a competitive market scenario, consumers make payments for the consumption of electricity to retailers at fixed tariff. The retailers buy power at the Market Clearing Price (MCP) in spot market and/or through bilateral contract at agreed upon price. Due to these different modes at buying and selling ends, the retailers are faced with an involved...

On current days, many of the power markets are adopting the practice of marginal loss pricing. The DC optimal power flow (DCOPF) model is still mostly used for the purpose of market clearing owing to its simplicity, robustness and higher speed of convergence. Within the DCOPF framework, transmission line losses are represented as additional externa...

Despite it's now well-known technical prowess, a large proportion of the Indian rural population still does not have access to electricity. Further, the Government of India has been exhorting private companies to participate in the national effort of extending electricity access to the rural consumer. However, private companies have to balance shar...

The Western Regional Load Dispatch Centre (WRLDC) has been successful in implementing the Power Network Analysis (PNA) sub-system of the Energy Management System (EMS) package supplied by M/s.GE after proper tuning of State Estimator(SE) to ensure that the SE output is suitable for use in real time grid operation. Usage of Contingency Analysis (CA)...

Common Information Model (CIM) is emerging as a standard for information modelling for power control centers. While, IEC 61850 by International Electrotechnical Commission (IEC) is emerging as a standard for achieving interoperability and automation at the substation level. In future, once these two standards are well adopted, the issue of integrat...

In order to guard forward contracts from the locational marginal price (LMP) volatility, financial transmission rights (FTRs) are issued in the centralized power markets. However, the current FTR system can provide hedge only against the congestion components of LMP differentials. Consequently, the loss components remain unhedged. To bridge the gap...

India is struggling to meet the electric power demands of a fast expanding economy. Restructuring of the power industry has only increased several challenges for the power system engineers. A major chunk of the power losses is a direct derivative of the poor management of distribution networks. Distribution automation (DA) has been aimed at reducin...

Point-of-connection (POC) scheme of transmission pricing in decentralized markets charges the participants a single rate per MW depending on their point-of-connection. Use of grossly aggregated postage stamp rates as POC charges fails to provide appropriate price signals. The POC tariff based on distribution of network sunk costs by employing conve...

Modelling of non-stationary time series using regression methodology is challenging. The wavelet transforms can be used to model non-stationary time series having volatility clustering. The traditional risk measure is variance and now a days Value at Risk (VaR) is widely used in finance. In competitive environment, the prices are volatile and price...

Financial transmission rights (FTRs) are complementary to the locational marginal pricing of energy. The basic aim of the FTR mechanism is to guard forward contracts from uncertain congestion charges. FTRs are also useful to individual generators and loads for selling and buying power, respectively, at the prices of other locations. The concept has...

Many developing countries like India have installed large number of constant speed wind turbine generators (WTGs) as they are robust and economical. Most of the countries have their own grid codes (rules and regulations) to integrate WTGs into the utility grid. One of the primary grid code for WTGs is low voltage ride through (LVRT) capability. The...

The transmission expansion planning (TEP) has long term effects on system performance. The effects are irreversible. The conventional optimization techniques have convergence problems for large system and heuristic methods reported so far are not holistic in nature. This paper proposes a two level approach. At first level, the usual static solution...

Broadly two solution approaches are used in solving the Transmission Expansion Planning (TEP) problem namely, Load curtailment minimization approach and Overload minimization approach. Overload minimization approach involves lesser computational efforts but has problem of non convergence of loadflow in presence of isolated nodes. In literature, iso...

The Electrical Engineering undergraduate programme at Indian Institute of Technology, Bombay (IIT-B) gives students an exposure to power engineering subjects, while the department offers a specialization in Power Electronics and Power Systems at the graduate level. Whereas the laboratories in power engineering are an integral part of both programme...

The renewable energy sources are going to become the long-term solution for future energy. Adequate infrastructure development is of crucial importance to harness power from them. This paper accumulates state-of-the-art issues and feasible solutions associated with large scale deployment of the renewable energy technologies. Various alternatives pr...

Introduction of competition in the generation sector has resulted in an interest for modeling the behavior of competitors for all strategic decisions. The behavioral model using conjectural variation (CV) will play a key role in the prediction of behavior of all constituents of power market. The conjecture of a firm is defined as its belief or expe...

This paper analyzes the implementability of locational marginal price (LMP) and financial transmission right (FTR) mechanisms in the presence of high voltage DC (HVDC) lines in the regulated (i.e., under the control of system operator) network. The established framework of LMP-FTR mechanism assumes that the system under regulation is fully AC. Unre...

This paper introduces the concept of multidimensional financial transmission right (MDFTR) which is a generalized group financial transmission right (FTR) concept. An MDFTR allows its owner to hold a total FTR amount over a path group along with multiple choices to distribute this grouped amount among the individual grouping paths. This added flexi...

Indian power sector is growing at an enormous pace. Building and operating such a power system is a challenging problem. The power network which carries the MWs across large distances is analogous to a "muscle system" of human body. Likewise, the entire range of associated monitoring and control network is analogous to a "nervous system". While str...

In restructured electricity markets, electricity retailers set up contracts with generation companies (GENCOs) and with end users to meet their load requirements at agreed upon tariff. The retailers invest consumer payments as capital in the volatile competitive market.In this paper, a model for quantifying price risk of electricity retailer is pro...

Conventionally, transmission fixed cost allocation is carried out on postage stamp basis. Amongst various other ways of solving the problem, the cost allocation under the "usage-based" domain has also been suggested, namely, based on proportionate tracing and recently, by optimization based real power tracing. Changing the cost allocation regime fr...

The power sector in India, one of the world's fastest growing economies, is undergoing a reforming process to keep pace with the new energy challenges. The government has embarked upon several structural and operational changes to revive the power sector, mainly focusing on bringing competition in different segments, setting up an independent regul...

The renewable energy sources are going to become the long-term solution for future energy. Adequate infrastructure development is of crucial importance to harness power from them. This paper accumulates state-of-the-art issues and feasible solutions associated with large scale deployment of the renewable energy technologies. Various alternatives pr...

This paper introduces concept of decoupled power controller for tracking load demand of an inverter-interfaced distributed generation (DG) system. The approach suggested in the paper uses reference frame theory to decouple quadrature axis and direct axis currents. As compared to the power-frequency droop based controller, the proposed controller de...

This paper presents an analysis of rotor speed stability of a constant speed wind turbine generator with active stall control. To analyze the rotor speed stability, a 3-phase short circuit fault on a sample system with a constant speed WTG has been simulated using DIgSILENT software package. From the simulation results, it has been shown that the o...

Megawatt (MW) power flow tracing can assess the extent of network usage by the participants that can be effectively used for multiple objectives like transmission pricing, loss allocation, etc. MW power tracing, a post-facto analysis of power flow solution, is amenable to multiple solutions. This implies multiplicity of solution space of transmissi...

Many developing countries have emphasis on DG technology for their generation expansion planning. The planning considerations and judicious choice of attributes is dictated by the prevailing conditions. With the increased complexities in DG planning options along with multiple attributes to be accounted, more sophisticated techniques are needed to...

Many developing countries have emphasis on distributed generation (DG) technology for their generation expansion planning. The planning considerations and judicious choice of attributes are dictated by prevailing conditions. The attributes considered are capital costs, energy not served per annum, and profits from injecting power into the grid at p...

Most of the tracing algorithms proposed so far are the variants of proportionality based tracing algorithm. However, proportional sharing is not an inherent characteristic of the system. It is a rule enforced to attain uniqueness of the solution in a fair manner. Under proportionate tracing regime, the bilateral transactions can be classified as tr...

In India the power sector reforms were initiated in 1991. It began with the participation of the private investors' in generation, and then focused on the unbundling of vertically integrated utilities. The Regulatory Commissions were formed in 1998 and the Electricity Act 2003 was enacted to accelerate the reforms. In states, the reforms were initi...

Hybrid optimization model for electric renewables (HOMER), developed by National Renewable Energy Laboratory (NREL), enables economic analysis for single source and hybrid distributed energy resources (DERs). However, current version of HOMER does not support microgrid analysis. In this paper, economic analyzer for distributed energy resources (EAD...

Real power tracing algorithms were invented to find the network usage by various generators and loads. Two versions of real power tracing are popularly quoted: linear equations based and graph theoretic based. Both the methods make use of proportional sharing assumption. When the directed graph of power flow is cyclic, the graph theoretic approach...

Amongst the commonly employed transmission pricing philosophies in the decentralized markets, i.e., point-to-point and point-of-connection (POC), the later one can be employed for both power exchange (PX) and bilateral trades. POC methodology charges a single rate per MW, depending upon the point of connection. The methodology though apparently sim...

Objective of this paper is to suggest a robust and easy-to-implement mathematical framework for dealing with simultaneous feasibility condition in financial transmission rights (FTRs) auction. The framework suggested is robust in the sense that it provides a purely analytical basis for clearing option and obligation FTRs simultaneously. Formulation...

MW power flow tracing was invented to assess the extent of network usage by the participants so as to allocate the transmission charges and losses. MW power tracing, a post-facto analysis of power flow solution, is amenable to multiple solutions. This implies multiplicity of solution space of cost and loss allocation problem. Existing tracing metho...

This paper describes the efforts of the Indian government to upgrade its power system to account for the increasing interconnections due to rapid regional development. These include the unibus act (EA2003), which addresses the issue of public sector monopoly and opens up the field for competition, private participation and reforms, and the implemen...

That regional interconnections can benefit interconnected grids is accepted by the decision makers owing to optimal utilization of resources, diversity of load patterns, increased security and improved system performance. However, there are "opportunities and threats" depending on how commercial, operational and security issues are tackled. The thr...

The distributed energy sources technology has progressed from isolated operation to hybrid and now to microgrid operation. The planning strategies initially considered cost-benefit analysis of distributed generation (DG). Later supporting advantages of the hybrid system including improvement of the efficiency were also considered for decision makin...

Power systems of many developing countries have to face sustained generation deficiency, large frequency fluctuations and are susceptible to even small disturbances. Operating such system is an onerous task and innovative solutions are needed to deal with the situation. To overcome the situation, India has adopted commercial mechanism known as avai...

In India, apart from state owned generators, a central sector power pool has been created consisting of central sector power stations. The Central Transmission Utility (CTU) has built an EHV network to transfer this power to the constituents of the regional network. To recover the costs incurred, the CTU levies the Transmission Service Charges (TSC...

Availability Based Tariff (ABT) has been implemented in all the regional grids of India for improving grid discipline by frequency dependent pricing. Currently it is limited to short-term energy transactions between the beneficiary States and Central generating stations without the need for negotiations on price or quantum in real time. In the pres...

Most tracing algorithms have used variants of proportionality based tracing algorithm. However, proportional sharing is not an inherent characteristic of the system. It is a rule enforced to arrive at a solution in a simple and fair manner. We propose a multi-commodity network flow optimization approach for optimal tracing of power flows. The resul...

Postage stamp allocation is unfair to those users who make limited usage of the network. MW power flow tracing was invented to assess the extent of network usage. MW power tracing, a post-facto analysis of power flow solution, is amenable to multiple solutions. This implies multiplicity of solution space of cost allocation problem. Existing tracing...

The need for restructuring the power sector was felt due to the scarcity of financial resources available with Central and State Governments, and necessity of improving the technical and commercial efficiency. Electricity Act 2003 has come into force from June 2003. As the act allows third party sales, it introduces the concept of trading bulk elec...

This paper discusses several significant features of various blackouts and restoration problems encountered during the several grid disturbances in Western Region (India) during the period 1988-2003. The delays in restoration are also due to problems along the restoration paths, communication problems, etc. However, the experience of blackouts help...

In a deregulated power industry a Genco bids in the optimal fashion in a day ahead market. The net gain is decided by Market Clearing Price (MCP) which in turn is dictated by other participants and prevailing market conditions. In this paper, the feasible set of bid strategies is evaluated for risk. Risk is quantified as the variation from expected...

Distributed Generation (DG) can help in reducing the cost of electricity to the costumer, relieve network congestion and provide environmentally friendly energy close to load centers. Its capacity is also scalable and it provides voltage support at distribution level. Hence, DG placement and penetration level is an important problem for both the ut...

A distribution system has certain distinguishing features which make it different and somewhat difficult to analyze as compared to a transmission system. Unbalanced loads, untransposed lines, single-phase and two-phase laterals are some of them. The distribution system needs to be analyzed on the three-phase basis instead of the single-phase basis....

Distributed generation (DG) technology is developing rapidly and many countries have plans to install large percentage of new generating units at dispersed locations. When fixed and variable costs are considered, then wind generation becomes an attractive alternative. With grid interconnection, one has to address the issues like interfacing, protec...

The optimal bidding for generation companies (GenCo) in the deregulated power market is an involved task. The problem is formulated in the framework of the Markov decision process (MDP), a discrete stochastic optimization method. When the time span considered is 24 hours, the temporal difference method becomes attractive for application. The cumula...

Not Available

M. N. Agostini, I. C. Decker, and A. S. e Silva comment on the paper by S. Pandit et al. (see ibid., vol.16, p.647-52, 2001). with respect to object oriented modelling and the numerical results. The original authors reply to the comments.

QR decomposition of a large sparse matrix is used to solve the linear least squares (LS) problem arising in power system state estimation. It can also be used to estimate rank of matrix (rank revealing QR decomposition). Its utility arises from the numerical stability offered by orthogonal transformations. In addition, a linear system of equations...