Abstract
The National Energy Regulator of South Africa (NERSA) has implemented an Incentive-
Based Regulation (IBR) scheme that either rewards or penalizes distributors on the System-
Average Interruption-Duration Index (SAIDI) and other network performance indices [1]. The
optimal placement of automatic reclosers (auto-reclosers) is seen as a cost-effective measure to
reduce the system-average interruption-duration index (SAIDI) impact along a medium voltage
(MV) feeder. An auto-recloser is seen as a function of distribution automation (DA), thus
reducing customer impact. A great advantage of a correctly implemented and operated DA
system can improve network reliability significantly. This dissertation evaluates the empirical
relationship between recloser placement and reliability from the perspective of control and
instrumentation within ESKOM. It also puts forward an additional performance-improvement
framework that can be implemented to achieve RAM (Reliability, Availability and
Maintainability) management. Loop automation functionality is also under discussion; this is a
Distribution-System Automation-scheme that restores the supply to the fault-free sections of a
network, if they have been disconnected, because of a fault in another section of the network.
Loop automation can also restore the normal network configuration automatically, when the
faulty section is repaired. The process of isolating the faulty section and re-configuring the
network to restore supply back to the fault-free sections is the first capability of Loop
Automation. This research investigation assesses two different scenarios, namely: A
conventional implementation of auto-reclosers on MV networks using Eskom reliability
standard; and (ii.) the findings of a case-study using this recloser implementation (loop
automation) to improve the reliability and the system’s performance. Results obtained are
presented and discussed.
M.Phil. (Engineering Management)