Capacitive divider substation

Modelling and dynamic systems analysis of instability in a capacitor-coupled substation supplying an induction motor

“…5, which is equivalent to placing a shunt resistor in parallel with C 2 of Fig. 1, makes the system more stable as the shunt resistance decreases [4], as Fig. 9 shows for two values of shunt resistance.…”

“…A ferroresonance filter is installed at CCS installations, essentially as a band-stop filter following the concept proposed by Bolduc et al [4], and is inserted from V out to ground in Fig. 1. The effects of such a filter on the Root Locus trajectory are indicated in Fig.…”

“…In the CCS installation supplying the 1.3 MW induction motor, a ferroresonance filter was unsuccessful in preventing SSR [3], while removing the filter did allow typical ferroresonance to occur. It is therefore unlikely that the SSR was caused or initiated by ferroresonance, which must not be overlooked when dealing with such systems and for which there are several tried and tested techniques for prevention [2,4,5].…”

Eskom experience with on-site field tests of a capacitive coupled substation

“…A supply voltage is made available through tapping off the lower layer of capacitors and fed via a series reactor, shunt harmonic filter and breaker to the load. The design for the Meru CCS, jointly done by a local supplier and Eskom, was adapted from previous applications [1,2].…”

“…Capacitive coupled substations (CCS) based on the CVT concept have been built and used successfully in Canada, Mexico and South America, ranging from 100 kVA to 170 kVA [1,2,3]. The design patented by IREQ, the research division of Hydro-Quebec, includes a shunt filter to prevent ferroresonance [4,5], which is a common problem in conventional instrumentation CVT's.…”