Dispatch Analysis of Off-Grid Diesel Generator-Battery Power Systems

Abstract

Abstract Diesel generator (DG)–battery power systems are often adopted by telecom operators especially in semi-urban and rural areas of developing countries. System dispatch is one of the key factors to hybrid power system integration. The contradiction between battery dispatch and DG dispatch in DG–battery power systems is that shallow and medium cycling is preferred for long battery life, while deep cycling is preferred for DG fuel and maintenance saving. In this paper, two dispatch regimes, A of full cycle charge strategy and B of partial state of charge (PSOC) strategy, and the corresponding SOC (state of charge) set points of the DG–battery power system are analysed and compared in terms of system operational expenditure (OPEX) and net present cost (NPC). The system OPEX mainly consists of fuel-related, filters-related and battery bank replacement costs. The simulation programme is established based on system efficiency calculations and battery charging regimes. The results show that (1) shallow cycling may bring long DG running time and high fuel consumption, while deep cycling is in favour of reducing DG running time and fuel consumption; (2) shallow cycling is in favour of battery life under Regime A, while deep cycling is in favour of battery life under Regime B; (3) depth of discharge (DOD)$$ \in $$[0.8, 1.0] leads to the lowest NPC for both Regime A and Regime B; (4) Regime B wins with not large difference before the battery bank replacement happened, and after then Regime A wins.