Damped AC for Commissioning & Diagnostic Testing of HV Cables by Paul Leufkens.
Reliable transport is fundamental for on- and offshore energy infrastructure and that implies maintaining strict quality control on all newly installed as well as service-aged cable connections. In this regard, important issues for any transmission grid operator to ensure reliable network operation and responsible asset management include: how best to detect risk of workmanship related defects on newly installed cable circuits in a sensitive yet non-destructive way; and how to perform non-destructive diagnostics on in-service cable circuits in order to determine their actual condition. Based on present IEC standards for power cables up to and above 150 kV operating voltage, test protocols after installation of power cables are limited to minimum manufacturer recommendations and do not meet the need to keep failure risk during operation as low as possible. By contrast, IEEE 400 and IEEE 400.4 standards recommend partial discharge monitored testing, for example using continuous or damped AC voltage (DAC). This presentation focuses on use of DAC for after-laying testing and diagnostics on all types of transmission cables, based on experience collected over more than 15 years and across many different power grids worldwide.