Transmission loss allocation-Part 1

Introduction

In the deregulated power market one of the most important issues is the allocation of transmission losses among market participants since system losses can typically represent significant portion of the total generation. The main difficulty of loss allocation is caused by the highly nonlinear and non-separable properties of the loss function.

A number of allocation schemes have been proposed in the literature [1-12].  Some approaches are based on DC power flow, while some use AC load flow for matching the calculation results and actual power flows. Some schemes are branch-power-flow based, while some focus on the branch-current based allocation techniques

I
The allocation is done in two ways.
(i) User Based
(ii) Transaction based

A:User Based Transmission allocation


The user based transmission allocation also done in three ways.

(i) Allocation only among producers(Generators)

(ii) Allocation only among Consumers (Loads)

(iii) Allocation only among producers and consumers(Generators and loads)

There are so many methods are available in the literature.I will just explain the method incorporating current injection model.

To solve the  Transmission Allocation Problem the power flow solution of that operating point should be available. Consider a power system or with Ng generator buses,Nl Load buses and 'M' transmission lines  the transmission allocation problem is defined as follows.

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Solution methodology


1. As per the equation A3 the  transmission loss for different coalitions are calculated for each transmission line.

2. The total transmission loss of that line is the grand  coalition values.

3. After getting all the coalition values the solution (core) is determined by  cooperative game theory.

4.The contribution of a particular generator for every transmission line is summed up to calculate in allocation of the transmission loss.

For allocation to Loads the same procedure is just reversed. For allocation of both generators and loads
Vnn=Zbus*diag(Ibus) and the reamining procedures are same.