GWPD-S-HFCT High-Frequency Current Transformer Partial Discharge Sensor

1. GWPD-S-HFCT Partial Discharge Sensor – Product Introduction

• The GoWatron GWPD-S-HFCT High-Frequency Current Transformer Partial Discharge Sensor consists of a split-core HFCT and an associated signal acquisition unit. It detects high-frequency partial discharge current pulses in cable earthing circuits.
• Installed around the cable screen earthing conductor, the sensor uses electromagnetic induction to detect high-frequency pulses without making an electrical connection to the monitored conductor. The acquisition unit provides signal acquisition, processing and data communication. Wired and wireless configurations are available to suit site requirements.
• The product is suitable for online partial discharge monitoring of cable joints, terminations and associated earthing circuits. Sensor locations should be selected according to the cable screen bonding arrangement, signal propagation paths and site interference conditions.

2. GWPD-S-HFCT Partial Discharge Sensor – Product Functions

(1) High-Frequency Partial Discharge Pulse Detection

• Detects high-frequency current pulses propagating through cable screen earthing circuits, providing signal data to help identify abnormal discharge activity.

(2) Split-Core Installation

• The split-core construction allows installation and removal without disconnecting the monitored earthing conductor, simplifying the addition of monitoring points to existing installations.

(3) Wired and Wireless Communication

• The wired version supports Modbus. Depending on the configuration, the wireless version supports LoRaWAN or a protocol for communication with the associated equipment’s IoT platform.

(4) Power-Frequency Synchronisation

• Synchronisation is provided through an external power-frequency reference, internal synchronisation or wireless synchronisation, depending on the configuration. The selected method provides a phase reference for phase-resolved partial discharge analysis.

(5) Monitoring Data Analysis

• When used with a compatible monitoring system, the sensor supports pulse data recording, phase distribution analysis and historical trend display to assist assessment of changes in insulation condition. Available analysis and alarm functions depend on the monitoring system configuration.

3. GWPD-S-HFCT Partial Discharge Sensor – Technical Specifications

4. GWPD-S-HFCT Partial Discharge Sensor – Operating Principle

• Partial discharge in power cables and cable accessories produces fast-rising, high-frequency current pulses. Some of these pulses propagate along the cable metallic screen and associated earthing circuits, where they can be detected by an HFCT installed around the earthing conductor.
• The GoWatron GWPD-S-HFCT uses electromagnetic induction to convert high-frequency pulse currents passing through its aperture into voltage signals. The acquisition unit then acquires, processes and transmits these signals.
• Using a power-frequency phase reference, the monitoring system can analyse pulse amplitude, repetition rate, phase distribution and trends to help identify abnormal discharge activity. Results should be assessed together with background interference, the cable screen bonding arrangement and sensor location. Without appropriate calibration, the measured voltage should not be directly interpreted as apparent charge expressed in picocoulombs (pC).

5. GWPD-S-HFCT Partial Discharge Sensor – Applications

(1) Online Monitoring of Power Cables

• Installed on suitable cable screen earthing circuits to monitor high-frequency partial discharge pulses and their trends.

(2) Cable Joint and Termination Monitoring

• Positioned on associated earthing circuits near cable joints and terminations to help identify insulation abnormalities in cable accessories.

(3) Switchgear Cable Compartment Monitoring

• Installed around the screen earthing conductor of a cable termination and connected to a partial discharge monitoring system through the acquisition unit.

(4) Substation and Industrial Power Distribution Monitoring

• Used for cable insulation condition monitoring in substations, power plants, renewable energy installations and industrial power distribution facilities.

(5) Monitoring Upgrades for Existing Installations

• The split-core design facilitates the addition of monitoring points to existing equipment. Installation must comply with applicable site electrical safety procedures.