Allocation of the Reactive Power Support Requirements in Multitransaction Networks

This paper presents a new physical-flow-based mechanism for allocating the reactive power support requirements provided by the generators in multitransaction networks. The allocatable reactive support requirements are defined with respect to the support required for the network with no transactions in place. The requirements in the presence of the proposed transactions are formulated as the sum of two specific components—the voltage magnitude variation component and the voltage angle variation component. The formulation utilizes the multitransaction framework used for the allocation of losses. The formulation leads to a natural allocation as a function of the amount of each transaction. The physical interpretation of each allocation as a sensitivity of the reactive output of a generator is discussed. The extensive testing indicates that the allocation scheme approximates with good fidelity the actual net VAr outflow from each generator and is able to deal effectively with the nonlinearities due to the generator reactive power limits. The numerical results also indicate that the proposed scheme behaves in a physically reasonable and intuitive way.