A. R. Abhyankar

A Transmission Pricing Mechanism Based on Power Tracing for Central Transmission Utility in India

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) over the constituents. The constituents are billed for network usage charges which are proportional to their allocated share in the central sector power generation. An ideal pricing mechanism would have been to find out the usage of the network by the constituents and charge accordingly. In this paper, a real power tracing based method for recovery of Transmission Service Charge (TSC) from the constituents of Western regional grid in India is proposed. The method uses proportionality based real power tracing to find out the network usage by various constituents. Loss allocation on EHV network to the various constituents is also done. Actual data of power flows over the EHV network of Western regional grid for one day is considered.

Assessment of Risk involved with Bidding Strategies of a Genco in a Day Ahead Market

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 amount of return from the market settlements for an hour. The problem is formulated for multiple participants using efficient frontier method. The risk evaluation is done for two sample systems with three and six Gencos. The results help in choosing a maximum return with minimum risk policy.

Electricity transmission pricing: tracing based point-of-connection tariff for Indian power system

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 simple, easy to implement and understand, entails the difficult task of fixing up the POC rates. Use of grossly aggregated zonal postage stamps as POC rates damps out the locational signals, while the use of LMPs to devise the spatially variate point charges fails to account for the transmission sunk costs. To overcome the above limitations, we propose a methodology to determine POC rates based on real power tracing. We introduce the concept of tracing based locational transmission price (LTP) which reflects participation of each node in the transmission line flows and hence the sunk costs of the associated lines. Thus, LTP transforms transmission usage of each node into spatially variate price signals. The proposal is specifically worked out for the Indian power sector where realistic data of 193 bus system of Western regional (WR) grid is used. The POC rates thus calculated would find their practical utility once the PX activity starts in India.

Multiple solutions approach to tackle circular flows in real power tracing

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 is not able to proceed further, while the linear equations based approach may or may not fail depending on the distribution matrix structure. In this paper, we propose a new paradigm of real power tracing algorithms in which we show that the tracing problem can be formulated as a linear constrained multi-commodity network flow optimization problem. By exploiting multiplicity of solution space in real power tracing, it is shown that the proposed method converges to a solution even in the presence of circular flows by virtue of its constraint modeling. Results on practical data of Western Regional Grid of India demonstrate the usefulness of the method

Tractability of bilateral transactions considering multiplicity of solution space in real power tracing

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 tractable, partially tractable or intractable, based on degree of tractability. In this paper, we develop the concept of optimal tracing whose objective is to enforce maximum tractability of bilateral transactions, while attaining least deviation from the proportionate sharing results, using multiplicity of solution space. The resulting optimization formulation is shown to be a sparse linear programming (LP) problem. A unified formulation that models lossy MW flow network and provides consistent results for generation and load tracing is presented. The maximum tractability is modeled as soft constraint in the formulation. Illustrative examples and simulation results on IEEE-30 bus system demonstrate the claims