scope:

Introduction

Commissioning an HVDC system is a very complex task which may affect more than the actual contract parties. The complexity and the diversified areas of concern during system testing require thorough planning and scheduling, cooperation of all parties involved, and complete and structured documentation.

System testing completes commissioning of an HVDC system.

It allows the supplier to verify the suitability of the station equipment installed and the functional completeness of the system; adjustments and optimization can be made.

The user is shown that the requirements and stipulations in the contract are met and that there is correlation with studies and previous off-site testing.

In adapting the HVDC system to the "real world" (the connected AC systems) various constraints may exist, which require coordination within the economic schedules of the AC system operators.

System testing proves to the public that tolerable values of phenomena concerning public interest are not exceeded.

Five (5) major aspects are subject to system testing:

- HVDC station equipment and DC line/cable/bus incl. earth electrode, if any

- HVDC controls and protection

- Environmental considerations

- AC/DC system interaction

- System performance

The following diagram shows the interrelation between these aspects:

Acceptance tests shall be defined between supplier and user in advance and may be performed at an appropriate time during the test schedule.

The testing sequence is best scheduled starting at local level with simple tests before Involving additional locations and the transmission system and more complex tests,

A system test plan has proven itself as a good means for planning and scheduling.

Complete and organized documentation of the system tests is to the benefit of both the supplier and the user, it shall form part of the project documentation and contain al! necessary oscillograms, logs, etc, and if necessary a commentary and references.