Power system stability analysis of cable based HVAC transmission grids with reactive power compensation
Authors
Dall, Laurids Martedal Bergholdt ; Foo, Yi Wern
Term
4. term
Education
Publication year
2016
Submitted on
2016-06-01
Abstract
This thesis presents a study of the electromechanical dynamics associated with the implementation of long HVAC cables in power transmission. Transient stability and large-disturbance voltage stability of generic multi-machine power systems is assessed by RMS simulations in DIgSILENT PowerFactory. The stability performance of the OHL base case system is compared against an equivalent cable system. Results show that the 100 % compensated equivalent cable system has longer CCT than the OHL base system in most cases. Increasing the SR compensation degree may improve the CCT, while voltage stability analysis show that undercompensation improve the V; P load-ability. The cable system displays larger Pmax than the OHL base system. An advantage of the cable system is the availability of switch-able SRs. By decreasing XSR during a large disturbance, the capacitive current generated by the cables is injected into the network to impose a voltage. Case studies show that SRswitching can improve system voltages. A smooth voltage recovery is achieved by sequentially switching the buses measuring the lowest voltages. Further work is required in order to generalize and quantify the properties of SR-switching.
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