Abstract
This paper proposes an easy modelling of interline power flow controller (IPFC) into Revised Newton Raphson current injection load flow method. In this model, the IPFC is represented as series impedances with shunt injected currents at its terminal buses. The target of control for active and reactive power flow can be achieved by calculating these currents as a function of the desired power flow and the buses voltage at the terminals of IPFC. In case of controlling the active power flow only, these currents are calculated with the same method. But the reactive power flow is released and calculated according to the system. The injected currents are updated and added into the original current mismatches vector of load flow algorithm. By using this model, the symmetry of the admittance and Jacobian matrices can still be kept and incorporating of IPFC becomes easy without changing the basic load flow computational program. Consequently, the complexities of the computer program codes are reduced. Numerical results based on the literature 5-bus, IEEE 57-bus and IEEE 118-bus systems are used to demonstrate the effectiveness and performance of the proposed IPFC model.
1. Introduction
Flexible AC transmission system controllers are playing a leading role in efficiently controlling the line power flow and improving voltage profiles of the power system network. These FACTS controllers can be used to increase the reliability and efficiency of transmission and distribution systems [1–7].
In general, there are two generations of these developed control devices; the first generation is based on the conventional thyristor switched capacitors and reactors, and tap changing transformers, while, the second generation uses the GTO thyristor switched converters as voltage source converters (VSCs).
6. Conclusions
This paper has presented an easy modelling of IPFC into Revised Newton Raphson current injection load flow analysis. The model is based on shunt injected currents at the ends of IPFC. These injected currents are updated during the iterative process according to the desired power flow, correction of buses voltage and system reactive power flow between the second auxiliary and received buses. By using this model, the original structure and symmetry of admittance matrix can still be kept. The incorporating of IPFC in load flow becomes easy without changing in the basic computational algorithm. Consequently, the complexities of the computer program codes are reduced. The IPFC parameters can be checked and if their values are within the limits or not during the iterative process. Also the developed model overcomes the problem which exists when only the IPFC links between two sub-networks. The Revised Newton current injection power flow program with this IPFC model is useful tool for power system planning and operation control of large scale power system. The developed IPFC model has been validated on the literature 5-bus, IEEE 57-bus and 118-bus systems with excellent performance characteristics
