PROBLEMS RELATED TO APPLIANCES IN AUTONOMOUS PV APPLICATIONS

摘要

This paper describes the work undertaken as part of lEA's Task 3 (Use of Photovoltaic Power Systems in Stand-Alone and Island Applications) PVPS Implementing Agreement. The long term objective of this work is to facilitate large scale dissemination of stand alone PV systems by addressing technical issues concerning load management, and by exploring cost efficient appliances management strategies, that can contribute to cost reduction through standardisation and modularity. One of the activities of this task is related to technical issues in load management and new applications; In a stand alone PV system, the characteristic of the load and its distribution on both a daily and a seasonal basis is important. A well matched load together with a carefully selected choice of appliances can lead to significant savings in terms of reduced need for PV and electricity storage capacity. Conversely, inefficient appliances and processes, standby loads and inappropriate loads such as electric stoves, will increase the requirement for expensive PV and storage capacity. Inappropriate loads are very often the origin of PV system malfunction or failure. Start-up power peaks, or reactive power and harmonic distortion can cause system signal instability and protective devices will close the system down. This paper presents a survey of real cases with load related problems in world wide applications, their effect on quality and cost of the service and the solutions that were adopted. One of the main conclusions of the work is the importance to integrate the choice of the appliance as much as possible to the PV rural electrification programs.