Development of an Advanced LCC-HVDC Model for Transmission System

This paper describes an advanced LCC-HVDC model developed in PowerFactory for National Grid under the background of Western HVDC link in UK. Unlike most of the HVDC models in different simulation packages, this model explicitly incorporates the Automatic Filter Switching control and On-Load Tap Changer (OLTC) control. The automatic filter switching control is designed to limit the reactive power exchange between the converter station and the connected AC system at all power transfer levels to be within acceptable range. The OLTC is designed to dynamically control the firing angle at rectifier side and extinction angle at inverter side within their desirable ranges. Under the PowerFactory environment the DIgSILENT Programming Language (DPL) is written to carry out the system setup and the DIgSILENT Simulation Language (DSL) model is used to implement the controller designs.