Reliability Improvement of the Hydro One Distribution System using Pad-mount Transformers

Abstract

Reliability in electrical engineering refers to the ability of power systems (transmission systems or distribution systems), to perform their intended function of providing an adequate supply of electrical energy to customers efficiently with a reasonable assurance of continuity and quality. Reliability studies are further classified into two categories: adequacy and security. Adequacy analysis is the examination of capabilities within the system to satisfy the customer load demand and system operational constraints. It does not include system dynamic and transient disturbances. System security follows system adequacy. Currently, the Hydro One distribution system is over-capacity in most populated regions, specifically the Mount Albert region. Further, with ageing assets and increasing anticipated future load growth, there is a need for temporary solutions to accommodate future commercial and residential load growth. The option of replacing ageing assets is not feasible due to high costs and implementation time, so alternatives must be looked at.

In this report, various alternatives including the use of pad-mount transformers to relieve distribution stations in the Mount Albert region are studied using CYME. Load flow analysis with CYMDIST is used to determine the feasibility of the alternatives. This provides solutions to accommodate future load growth in the region. This will improve the reliability of the region to reduce power quality and low voltage concerns. This will help Hydro One accommodate immediate load growth and address reliability concerns in the short term.