How is the best way to maximize CAPEX/OPEX for SAIFI/SAIDI improvement?

The usual question from our clients is how to maximize CAPEX and OPEX to improve SAIFI/SAIDI in their electrical distribution networks.

There are different approaches that can be used depending on the final objectives, and a balance needs to be achieved between infrastructure cost options, maintenance, and network performance.

Many utilities cannot adequately measure the reliability inherent in the asset base, nor can clearly identify the wide variety of improvement initiatives required to achieve specific reliability targets, nor can they quantify the risks associated with changing maintenance or construction standards.  For many companies, the annual investment planning process is primarily one of negotiation around a constrained budget.

Developing optimal reliability improvement plans requires the detailed analysis of mountains of information: circuit configurations and connectivity, failure root causes, interruption duration data, preventive and corrective maintenance policies, outage mitigation costs and others. In the absence of a specific approach, the investment allocation process will always return a suboptimal plan.  If the business cannot quantify the reliability impact of each maintenance and investment intervention, it cannot measure or manage asset reliability - or minimize spend without unknown failure risks.

To solve the question and to be able to provide a solid answer to our clients, we apply a methodology and use a predictive model that allows to simulate the impact on SAIFI/SAIDI of different types of CAPEX/OPEX interventions.

The methodology considers environmental, geographical and area characteristics, like lightning, pollution, vegetation, typical networks for each area, and customers density.

Proper asset management optimization ensure that assets performance will not be deteriorated over time in relation to the quality of service and is the way to improve performance at optimum cost.

To analyze infrastructure cost options, we explore four types of CAPEX interventions:

● Additional equipment on the existing network without topology changes (reclosers, fuses, breakers)

● Circuit loops, providing the possibility of network reconfiguration.

● Shorten the line through automatisms to minimize the impact on affected customers.

● Additional HV/MV substations to increase the number of feeders and reduce its length.

For each type of CAPEX intervention several simulations are made to analyze up to what level SAIDI could be reduced by increasing the investment.

  To solve the question and to be able to provide a solid answer to our clients, we apply a methodology and use a predictive model that allows us to simulate the impact on SAIFI/SAIDI of different types of CAPEX/OPEX interventions. 

Typical results show that for SAIDI improvements of ~15% the best options are the inclusion of additional equipment or Circuit loops. Between these two options it would depend on network characteristics and circuit loops possibilities introduction.

Further SAIDI improvements would require a line length reduction, splitting the existing ones or introducing new substations and new feeders.