IEC PAS 61975:2004 pdf download System tests for high-voltage direct current (HVDC) installations
Logical Steps of Commissioning
System commissioning should follow the structure of the HVDC system, startingfrom the smallest, least complex operational unit, usually a 12-pulse converter,and shall end with the total system in operation.
The first step, to ensure proper function, is to debug and test the control systemduring factory system tests. Because of the complex nature of the HVDCsystem, this requires a simulator. Where applicable, it is recommended to runcommissioning tests and acceptance tests in addition to ail limiting design caseson the simulator in a similar way to those done later at site. In such a waysimulator tests can serve as reference for the site tests.
Before system commissioning can begin at site the following preconditionsshould be fulfilled.
All subsystems tested and commissioned including AC filters and theconverter transformers with special attention to possible transformer/AC filterresonance during energizing
Sufficient training of operating personnel
Operating instructions for the station available to the operators
Personnel, plant safety and security instructions made
System test plan and documentation (part 8) ready and agreed upon
AC/DC power profiles agreed for each test
Any AC/DC system operating restrictions identified
Operator voice communications available
All necessary test equipment calibrated and operational
Procedures for the preparation and evaluation of test results agreed upon
After all preconditions are fulfilled, each converter unit is commissionedseparately. Open-circuit tests and/or short-circuit tests are possible for thispurpose. Steady-state performance and interference tests may start at thisinstant; however, they can be performed one by one at any convenient otherplace dying the system test program, in order to minimize duplication of tests.
If possible, as a next step the converters in each station should be connected back-to-back. This allows full active power with the nominal DC voltage, firing angles, harmonics, etc. whilst still disconnected from the second AC system. Certain control, relaying and instrumentation changes as well as temporary DC switchyard changes may be required for back-to-back tests.
Before full end-to-end tests are performed, it is advisable to perform an open line test and shorted line tests with the DC transmission line. This test can be repeated from both ends to verify the integrity of the DC line.
End-to-end tests will then be conducted. These tests involve both stations and the transmission line. With this operation power is transmitted for the first time. This test is usually done on a monopolar basis first, with full bipolar operating being the final step.