Partial Discharge (PD) testing is an essential method for evaluating and monitoring the insulation condition of GIS high-voltage switchgear and transformers. The main reasons and significance of PD testing include the following:
1.Early Defect Detection and Warning
Partial discharge is a localized weak discharge phenomenon within the insulation system, often caused by the presence of micro-bubbles, cracks, impurities, aging, or manufacturing defects. PD testing can detect these hidden issues at an early stage, preventing the long-term degradation of the insulation system and stopping minor defects from evolving into major failures.
2.Ensuring Insulation Performance
GIS high-voltage switchgear and transformers operate under high voltage, complex environments, and gas insulation conditions. If partial discharge is not controlled, it can lead to localized deterioration of insulation materials, accelerating insulation aging and even causing insulation breakdown. Regular PD testing helps assess the health of insulation materials, ensuring stable insulation performance and operational safety.
3.Preventive Maintenance and Lifespan Management
By monitoring partial discharge signals, operators can evaluate the condition of the equipment and schedule timely maintenance or replacement, achieving preventive maintenance. This not only prevents unexpected failures but also extends the service life of the equipment, ensuring the long-term stable operation of the power system.
4.Quality Control and Process Optimization
Conducting PD testing during the manufacturing and installation stages helps identify defects in design, production, or installation processes. Timely feedback and corrections improve product quality and overall process standards, reducing operational risks in the later stages.

GTPD-4C partial discharge comprehensive tester is the new generation of digital PD measurement and analysis instrument. The instrument has a strong ability of comprehensive analysis of partial discharge and detection of partial discharge in small signal and strong interference environment. With different accessories, it can measure and locate the partial discharge in any high voltage electrical equipment. It can realize testing the transformer partial discharge by applying the voltage on the three phases simultaneously.

Functions and Feature:

1. Multi signal channel, desktop, TFT liquid crystal display, reliable system, low failure rate, strong anti- interference ability.

2. It integrates functions of measurement, diagnosis, location and on-line monitoring.

3. The location of fault position can be achieved by electro-acoustic and acoustic-sound.

4. According to the testing process, the test report can be generated automatically and the report can be read and printed.

5. The replay function can restore the saved data file to the waveform displayed on the screen.

6. Four channels electrical signal and four channels optical signal input port can simultaneously realize the measurement and analysis of multi-channel partial discharge signal.

GTPD-4C PD Tester Specification

Technical characteristics	Channels	Independent 4 one for external	Nonlinear error of this range	5%
	Sampling frequency	1M, 5M, 10M (optional)	Measuring range	0.1pC~1000nC
	Sampling accuracy	12bit	Sensitivity	0.1pC
	Measuring range	×1, ×10, ×100, ×1000, ×10000, ×100000	Capacitance range of specimen	6pF~250µP
	Measuring bandwidth	10kHz~1MHz (3dB Bandwidth)	External synchronous frequency  input range	30Hz~400Hz
	Digital filtering	10kHz~1MHz (Arbitrary choice)	External synchronous voltage input range	10V~400V
	Programmable filter segment	Low frequency:	Power supply	AC220V, Frequency: 50Hz (customized)
		10kHz, 20kHz, 40kHz, 80kHz OFF(10kHz)
		High Frequency:
		100kHz, 200kHz, 300kHz, 400kHz 800kHz,OFF(1MHz)
Display	Display screen	12 inch TFT true color touch LCD screen	resolution	1024×768
Interface	USB, Power interface, optical signal interface, electrical signal interface, RJ45 internet interface, grounding button
Common description	Operation system	Windows XP	CPU	1.6GHz
	Size	474×288×370mm	Memory	2.0GB
	Weight	15.8kg	Hard disc	128GB Solid state hard disk

GTPD-4C PD Tester Application

turn ratio tester, transformer test instrument, winding resistance tester, transf