Reliability and life expectancy of modern SCADA equipment in underground installations: SCADA Equipment in PG&E secondary undergroud distribution networks

Abstract

Supervisory Control and Data Acquisition (SCADA) and monitoring systems are widely used in power infrastructure, including transmission, distribution and secondary network systems. This paper presents a research that primarily addresses the reliability and life expectancy of SCADA and monitoring equipment installed in secondary underground network systems of the Pacific Gas and Electric Company (PG&E) company, which serves areas where safety and reliability are critical. The equipment is installed in underground vaults and includes sensors, remote terminal units, communication switches, backup batteries and fiber cables. This equipment is exposed to harsh underground environmental conditions. Detrimental effects of these environmental conditions, such as moisture, corrosion and resistive contaminations, could potentially affect the reliability and accuracy of the monitoring devices. This paper presents the findings of the research that Exponent has performed on PG&E's SCADA equipment used in the secondary underground networks of San Francisco and Oakland in California. The research included the life expectancy of the existing equipment and effects of local conditions, integrity and reliability of the electrical connectors and monitoring sensors, methods to increase life expectancy, and the associated human factors and economics related to maintenance of the underground monitoring equipment. Factors affecting performance of the studied equipment are discussed and suggested methods to improve the reliability and life expectancy are outlined.