Partial Discharge (PD) is a localized electrical discharge within a high-voltage equipment's insulation driven by non-uniform field distribution or dielectric weakness. Because it does not completely bridge the entire insulation path, the primary insulation remains intact, fundamentally distinguishing PD from a complete breakdown that causes immediate short circuits. These discharges predominantly originate at microscopic air bubbles, cracks, or solid impurities embedded within the insulation.
High-voltage apparatus like transformers, cables, and GIS utilize composite insulation systems of oil, paper, or epoxy resin. Since the dielectric constant (ε) of trapped air gaps is significantly lower than that of the host material, the electric field intensity across these gaps distorts and spikes under high voltage. Once a critical threshold is exceeded, the air ionizes, initiating a partial discharge. Manufacturing flaws, moisture ingress, thermal aging, and overvoltage impulses are the primary catalysts. Beyond generating corrosive gases, continuous electron bombardment and localized overheating trigger "electrical treeing" within solid insulation. This cumulative damage erodes the dielectric path over time, ultimately leading to catastrophic equipment failure or explosion. For this reason, PD is universally dubbed the "invisible killer" of high-voltage insulation.
Below is a curated selection of the world's top 8 manufacturers of high-voltage PD test systems. Renowned for ultra-low noise thresholds, advanced noise-suppression algorithms, and exceptional field stability, these premier brands represent the industry gold standard—delivering authoritative, interference-free diagnostic data to safeguard your critical power assets.
Founding Year:1889
Current Status: Global market leader in electrical test equipment with manufacturing sites in the UK, US, Germany, and Sweden, serving over 130 countries.
Core Business Scope: High-voltage asset diagnostics, cable fault location, protection relay testing, and online/offline insulation analytics.
Key Features & Strengths:Deep application expertise following the acquisition of PD specialists like Power Diagnostic Systems (PDI). Exceptional hardware ruggedness and highly integrated diagnostic software for pattern recognition.
Flagship PD Tester: UHF PD Detector (handheld online PD surveyor), ICM compact / ICM flex series (advanced PD detectors for laboratory and field diagnostics).
Website: https://www.megger.com
Official Email: sales@megger.com
Founding Year:1984
Current Status:Top-tier global multinational headquartered in Klaus, Austria, with 22 international offices supplying testing solutions to grid operators in over 170 nations.
Core Business Scope: Primary and secondary asset testing, condition monitoring, electrical diagnostic software, and high-voltage PD consulting.
Key Features & Strengths: The undisputed global standard for high-precision, synchronous multi-channel PD measurement. Superior digital noise suppression and fully automated PRPD (Phase-Resolved Partial Discharge) analysis.
Flagship PD Tester: MPD800 (state-of-the-art universal PD measurement system), MONALOS (continuous online PD monitoring system for rotating machines).
Website: https://www.omicronenergy.com
Official Email: info@omicronenergy.com
Founding Year:1966
Current Status:World-renowned power asset management specialist headquartered in Chester, UK, operating global subsidiaries across Europe, North America, and Asia.
Core Business Scope:Asset management consultancy, network center smart grid solutions, and specialized instruments for non-invasive PD detection.
Key Features & Strengths:Pioneers of Transient Earth Voltage (TEV) and airborne ultrasonic PD detection technology. Highly respected for developing data-driven asset reliability models and non-intrusive testing protocols.
Flagship PD Tester: UltraTEV Plus2 (multifunctional handheld PD locator), CableData Collector (online PD testing for medium and high-voltage cables).
Website: https://www.eatechnology.com
Official Email: sales@eatechnology.com
Founding Year:1920
Current Status:Subsidiary of ESCON Group, headquartered in Marlborough, Massachusetts, USA, providing diagnostic instruments and engineering services globally.
Core Business Scope:Substation asset diagnostics, insulation condition monitoring, protection testing, and enterprise data management software.
Key Features & Strengths:Extensive global database of asset health signatures. Superb correlation of PD data with acoustic, RF, and chemical markers (DGA), paired with premium field service support.
Flagship PD Tester: PDS100 (Surveyor handheld RFI and EMI detector), Doble Spark P3 (portable acoustic and electromagnetic PD analyzer).
Website:https://www.doble.com
Official Email:customerservice@doble.com
Founding Year:1948
Current Status:Operating as a prominent subsidiary of Fortive Corporation, headquartered in Everett, Washington, USA, with comprehensive global distribution networks.
Core Business Scope: Electronic test tools, thermal imaging, industrial calibration equipment, and acoustic imaging solutions.
Key Features & Strengths: Industry leader in user-friendly, non-contact acoustic imaging. Highly accessible commercial architecture that transforms complex sound wave matrices into clear visual hot spots without asset downtime.
Flagship PD Tester: Fluke ii910 Precision Acoustic Imager (detects corona, tracking, and arcing PD from safe physical distances).
Website:https://www.fluke.com
Official Email:sales@fluke.com
Founding Year:1984
Current Status:Leading global supplier of automated test equipment (ATE). Headquartered in Taoyuan, Taiwan, with major engineering centers in Europe, the US, and mainland China.
Core Business Scope:Precision power testing, EV test systems, semiconductor packaging equipment, and component safety testing.
Key Features & Strengths:Exceptional manufacturing integration and structural testing automation. Specializes in embedded PD detection during high-voltage component production lines to eliminate infant mortality defects.
Flagship PD Tester: Chroma 19036 (Multi-channel Wound Component EST Analyzer with integrated PD testing), Chroma 19311 Series.
Website:https://www.chromaate.com
Official Email:info@chromaate.com
Founding Year:2003
Current Status:Highly specialized German boutique engineering firm based in Eltmann, Lower Franconia. It maintains a strong global footprint among semiconductor and high-voltage component manufacturing plants.
Core Business Scope:Development, manufacturing, and automation integration of non-destructive high-voltage test sets and standardized partial discharge measurement systems.
Key Features & Strengths:Focuses completely on delivering "messbarer mehrwert" via strict adherence to international testing standards like IEC 60270, VDE 0884, and IEC 60747-5-5.Exceptional agility in software development and custom PLC automation, embedding PD testing loops directly into client production lines.
Flagship PD Tester: TTS Series & TPP Series (Integrated high-voltage insulation and partial discharge test benches), TMG Series (High-precision digital partial discharge meters), and TPK/TPK-H (PD high-voltage pulse calibrators).
Website:https://pd-tester.com
Official Email:info@mps-systeme.de
Founding Year:2009
Current Status: Kingrun is one of China's earliest manufacturers of transformer and power grid testing equipment. Renowned for the stability of its product quality and exceptional cost-effectiveness, Kingrun maintains its own independent PD laboratory and R&D team to ensure the high precision and stability of its testing instruments, and has established itself as a trusted long-term supplier to Hitachi, Siemens, and ABB.
Core Business Scope:Transformer winding resistance meters, turns ratio testers, circuit breaker diagnostics, and substation PD surveying instruments.
Key Features & Strengths:Strong agile manufacturing footprint. Exceptional focus on handheld, field-ready instruments with high cost-to-performance ratios and intuitive color touchscreen interfaces for utility crews.
Flagship PD Tester: GTPT-92 Portable partial discharge tester (supporting multi-sensor TEV, ultrasonic, and UHF detection fields). GTPD-4C: 4-Channel, Full-Featured PD Tester;GTPD-3 Ultrasonic partial discharge detector
Website:https://www.kritester.com
Official Email:info@kritester.com
