R1500 – High-Voltage Bushing Insulation Monitoring System
High-voltage power transformer bushings – both oil-filled and solid – are important transformer elements, as the transformer operation reliability depends on the bushing condition.
"R1500" transformer insulation monitoring system is used for on-line condition monitoring of three power transformer bushings. The system monitors several important parameters reflecting the condition of transformer bushing insulation, such as:
- Bushing leakage current imbalance of the three phases.
- Insulation dissipation factor and bushing capacity.
- Temperature dependence of the bushing parameters, which occurs when there are problems in bushing isolation.
- Time trend in bushing parameters changing, which indicates defects development.
"DB-2" sensors used in the monitoring system have many constructive modifications. The sensors get complex signal from the bushing test taps. This signal includes bushing leakage current of power frequency and high-frequency partial discharge (PD) signal. The bushing leakage current is used in "R1500" system; for PD measurement a portable device can be safely connected to the special slots of "R1500" system.
"R1500" device measures relative dissipation factor in bushing insulation, when the parameters of one bushing are compared to those of the other two. "R1500" device can measures absolute dissipation factor in insulation - tgδ. It can be done for the three bushings of one transformer. The feature of the measuring circuit is the possibility of HV and LV bushings comparison in different combination.
"R1500" device processes the information from primary sensors and makes reports about the bushing insulation condition.
All the measurements are saved in volatile memory. The information is uploaded into SCADA through RS-485 interface.
Special software for storage and analysis of the information about bushing condition is supplied together with the system. It allows more detailed analysis of the primary information.
"R1500" system has two automatic relays switching on when warning and alarm thresholds are exceeded.
"R1500" system is meant for installation in the enclosure near the monitored transformer. All the device elements can operate in the temperature range from -40 °C.
"R1500" system can operate in the temperature range from -55 °C and ambient humidity up to 95% without condensation if additional heater is installed inside the enclosure.
"R1500" System Specifications
|The number of monitored bushings with oil-paper and RIP insulation||3|
|The number transformer tank temperature measurement channels||3|
|The number of load current measurement channels in phases||1 (3)|
|The number of ambient humidity measurement channels||1|
|Rated voltage, kV||110 ÷ 750|
|Relay input parameters (dry contact)||5A, 220V|
|Communication ports||RS-485, USB|
|Supply voltage, AC/DC V||AC/DC 120 ÷ 260|
|Power supply, with heating, W||< 100|
|"R1500" enclosure dimensions, mm||400 * 530 * 210|