STUDY OF DISTRIBUTED SLACK BUS MODEL FOR ECONOMIC DISPATCH OF RENEWABLE ENERGY

M Abdulhamid,O Billy

doi:10.20535/1813-5420.2.2019.190023

Abstract

In this paper, a distributed slack bus (DSB) using combined participation factors based on scheduled generation capacities of the system is designed in order to distribute the system losses among the generators. A DSB algorithm is developed and implemented using a Newton Raphson (NR) solver on a MATLAB platform. The IEEE 14 bus is used as a case study. Renewable energy (RE) sources are introduced into the system and the generation cost compared between systems with renewable energy sources and those with only thermal generators in both the single slack bus (SSB) model and the DSB model. The DSB employed resulted in a reduction in overall real power generation from 272.593 MW to 272.409 MW in the 14 bus model and cost of generation also decreased in both buses. Real power line losses also reduced in the buses. The change in the generation levels of the voltage controlled buses resulted in a proper economic dispatch scheme which gave an accurate representation of the network parameters. The cost of generation is considerably reduced upon introduction of wind and solar generators into the system as compared to systems without these sources. An even more accurate network model is obtained by using combined participation factors.

Highlights

Economic dispatch is the process of ensuring that the total load is appropriately shared the generating units operating in parallel in a power system
This paper develops a distributed slack bus algorithm based on reactive power participation factors as follows: Step 1: Read system data and formulate Ybus Step 2: Initialize bus voltage magnitudes |Vi|, phase angles δ and set initial QLoss = 0 Step 3: Set iteration counter K = 0 and convergence criteria ε Step 4: Set initial values of Qgi and determine initial reactive power participation factor Kt0 Step 5: Compute Pi (k) and Qi (k) for system buses using the equations: n
Generation cost: distributed slack bus (DSB) reactive with Renewable energy (RE) cost: 757.623 $/Hr DSB reactive thermal cost: 834.150 $/Hr Convergence achieved after: 4 iterations the total cost is: DSB with RE using combined PF (Thermal): (4801.906*0.8) + (834.150*0.2) = 4008.3548 $/Hr DSB with RE using combined PF (With RE): (4768.870*0.8) + (757.623*0.2) = 3966.6206 $/Hr

Summary

Introduction

Economic dispatch is the process of ensuring that the total load is appropriately shared the generating units operating in parallel in a power system. It uses two notions as its basis, the first is that the generating units must provide for the load requirements of the power system within the minimum cost bracket by optimally using the units. The slack bus is the bus that provides additional real and reactive power to supply the transmission losses in a power system. It is taken as the reference where the magnitude and phase angle are taken. It is the reference bus for voltage measurements [1]

Methods

Results

Discussion

Conclusion