500 kV Cable AC Withstand Voltage Testing with Sieyuan HV AC Resonant Test System

The Guangzhou Chuting 500 kV Power Transmission and Transformation Project involved the installation and commissioning of approximately 20 km of 500 kV XLPE cables. The long cable length required the AC withstand voltage test system to provide sufficient charging capacity to support high-voltage testing requirements. Meanwhile, the limited on-site space required a high-capacity system design to simplify equipment lifting, installation, and wiring, thereby reducing the complexity of on-site setup and testing.

An HV AC resonant test system with sufficient test capacity and stable long-duration operation was therefore required to support the on-site cable testing process.

• Insufficient On-Site Power Supply Capacity — The 500 kV long cable test requires a large charging capacity, which places high requirements on the input power capacity of the complete test system and the conversion efficiency of the variable-frequency test power supply.

• Low Temperature Rise Operation Requirement — Large-capacity test systems face the challenge that conventional test reactors may experience excessive temperature rise, reduced service life, and even thermal damage during prolonged high-voltage testing.

• Complex Site Conditions — The site area is limited, so hoisting and wiring of the complete equipment set had to be simplified to reduce the complexity of on-site installation and testing.

• Single-Unit High-Power Variable-Frequency Power Supply — Sieyuan adopted a single-unit 1,200 kW variable-frequency test power supply together with a single high-Q test reactor, reducing the required on-site input power and simplifying system coordination.

• High-Q, Low-Loss Test Reactor — The high-Q iron-core test reactor reduced power loss and temperature rise during long-duration high-voltage operation, supporting stable testing performance.

• Simplified System Configuration — The single-power-supply and single-reactor configuration avoided the need to parallel multiple lower-capacity units, reducing risks associated with uneven current distribution and local overheating while simplifying system wiring and commissioning.

• 1,200 kW Variable-Frequency Test Power Supply — Provides the active input power required to drive the resonant test system.

• High-Q Test Reactor — The iron-core test reactor features a quality factor (Q) of ≥ 200, with low power loss and low temperature rise.

• Up to 100 km Cable Testing Capability — The system is designed to support cable test lengths of up to 100 km. For the Guangzhou Chuting project, the actual cable test length was approximately 20 km.