Every partial discharge couples into the surrounding equipment in several ways at once: as an electromagnetic wave inside a metal enclosure, as a conducted current pulse along the earth path, and as airborne sound. Each coupling path carries complementary information, and the more paths a monitoring point captures, the more confident the diagnosis. The combined UHF and pulse current sensor is built on this idea: one sensor that couples both the ultra-high-frequency wave and the conducted pulse of the discharge. This article explains the HUWOR HMJ1010-WGP.
Why combine UHF and pulse current
UHF coupling measures the electromagnetic wave radiated by the discharge in the 300-1500 MHz band. It is the most sensitive method inside metal-enclosed equipment such as GIS and transformer tanks, and it is highly immune to external corona and switching noise.
Pulse current coupling measures the high-frequency current pulse that the discharge injects into the conductor or the earth path. It is a direct, broadband measurement that captures the charge transfer of each discharge event and is the classic method for calibrating discharge magnitude.
Combined, the two paths give a more complete picture: the UHF channel confirms that the activity is internal and located in the enclosed volume, while the pulse current channel measures the magnitude and supports comparison with other measurements on the same circuit.
The HMJ1010-WGP at a glance
The HMJ1010-WGP is a UHF and pulse current partial discharge sensor designed for continuous online monitoring of partial discharge activity in medium- and high-voltage electrical equipment. According to the published specification, the UHF frequency range is 300-1500 MHz, measured under the reference conditions stated in the datasheet.
The sensor integrates both coupling elements in one unit and feeds both channels to the monitoring platform, so one installation point provides the two independent views without a second sensor.
Where the combined sensor is the right choice
The HMJ1010-WGP fits projects where both coupling methods are meaningful and the installation cost is dominated by the monitoring point, not the sensor:
- GIS circuits with cable connections, where the UHF channel covers the GIS compartment and the pulse channel covers the cable termination at the same location
- Transformer monitoring, where the UHF channel reads the tank interior and the pulse channel reads the bushing or neutral connection
- Long cable circuits, where both the radiated and conducted signals help locate the discharge along the route
In these applications the combined sensor avoids a second mounting point, a second cable and a second channel on the monitoring unit.
Using the two channels in diagnosis
The platform displays the UHF and pulse current channels together. A discharge event that appears on both channels at the same instant is a genuine internal discharge with a measurable magnitude – the strongest evidence for a repair decision. When the channels disagree, the discrepancy itself is diagnostic: a pulse current reading with no UHF confirmation suggests a conducted disturbance, while a UHF reading with no pulse component suggests a radiated source outside the conducted path.
Summary
The combined UHF and pulse current PD sensor gives one monitoring point two independent views of the same discharge: the radiated 300-1500 MHz wave and the conducted pulse. The HMJ1010-WGP brings this dual coupling to GIS, transformer and cable projects where confidence in the diagnosis matters. HUWOR supplies the sensor with OEM/ODM support. Contact the HUWOR sales team for specifications.