New Cost-effective Method for Monitoring Wideband Disturbances at Secondary Substation
|Kustantaja||Tampere University of Technology|
|Tila||Julkaistu - 4 toukokuuta 2018|
|Nimi||Tampere University of Technology. Publication|
Secondary substations seldom have any remotely readable measurement and control units and the existing measurements in the network are limited to only power quality and MV fault management due to low sampling rate (some kHz). There are also commercially available devices for PD monitoring of underground cables but those capable of continuous on-line monitoring are still relatively expensive and as such, more suited for critical and high risk location. Currently, there are no cost-effective wideband multifunction devices suitable for continuous on-line PD monitoring, PQ monitoring, disturbance recording (DR) and fault location at secondary substation.
This thesis proposes a novel cost-effective secondary substation monitoring solution which includes the monitoring system as well as the monitoring concept to measure various quantities at LV and MV side of secondary substation. Additionally, it can be used in fundamental frequency metering and can be used as disturbance recorder as well. It also locates earth fault which is demonstrated as an application of disturbance recording function. The architecture of the monitoring system includes high frequency current transformer (HFCT) sensors for current measurements at MV side, resistive divider for voltage measurements at LV side, filter & amplifier unit and multichannel data acquisition & processing unit. HFCT sensors not only measure PD but also PQ at the MV side of secondary substation, which is a novel approach. Hence, no sensor having expensive high voltage insulations is needed, which makes the solution cost-effective and reliable. The overall concept is tested and verified through prototype systems in the laboratory and in the field. Secondary substation monitoring solution provides a platform on which various monitoring, control and network automation applications can be built.