A new range of single rod live-line capacitor assemblies for use on system voltages up to 36kV has been announced by Morgan Advanced Materials. Constructed from ceramic dielectric materials that exhibit a high AC breakdown strength, the new range can operate continuously on a 36kV system line, and a negligible change of capacitance with applied voltage.
They also offer a significant volumetric efficiency saving over designs where two rods are connected in series to meet voltage test requirements.The capacitor range complies with all qualification and routine production tests as detailed in IEC60358, which include a power frequency test to 70 kV RMS/min, the ability to withstand a lightning impulse of 170kVpeak and partial discharge capability of less than 5pC at 40 kV RMS. The new range boasts a capacitance range of 15pF – 80pF with dimensions (including two brass terminals) 17mm diameter x 81mm in length.
Live-line capacitors are built into capacitor divider circuits which are connected to medium system voltage lines where they are used to sense the presence of voltage. The signal derived from the low voltage side of the capacitor divider can also be used to monitor supply failure and circuit conditions.
Dave Edwards, HV&RF technical manager for Morgan Advanced Materials, said: “This latest extension of the range has been made possible by increasing the breakdown strength of selected materials and will offer design engineers significant cost and space savings over current designs. Our capabilities also allow us to offer customised solutions for both live-line applications and power line coupling communication (PLCC) capacitors.”