Power system stability analysis of cable based HVAC transmission grids with reactive power compensation
Translated title
Authors
Term
4. term
Education
Publication year
2016
Submitted on
2016-06-01
Abstract
This thesis presents a study of the elec- tromechanical 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 PowerFac- tory. The stability performance of the OHL base case system is compared against an equivalent cable system. Results show that the 100 % compensated equivalent cable sys- tem has longer CCT than the OHL base sys- tem in most cases. Increasing the SR com- pensation degree may improve the CCT, while voltage stability analysis show that under- compensation 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 dis- turbance, the capacitive current generated by the cables is injected into the network to im- pose a voltage. Case studies show that SR- switching can improve system voltages. A smooth voltage recovery is achieved by se- quentially switching the buses measuring the lowest voltages. Further work is required in order to generalize and quantify the proper- ties of SR-switching.
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