Operational Experience with Composite Insulators at HVDC Substations
After 40 years of operating experience, composite insulators for HVDC applications are now recognized as a mature alternative to porcelain, with low flashover rates and no significant ageing or deterioration observed. With a growing HVDC technology market due to sharply increased power demand, the number of composite insulators for DC applications is expected to increase greatly by 2030 due to their advantages when installed at UHV DC stations in polluted regions. This presentation reviews service experience based on assessment of DC composite insulators and bushings in operation at outdoor DC yards at HVDC stations. Moreover, it provides recommendations for qualification of composite insulators for HVDC applications with respect to crucial design parameters, including material and shed design.