The classification of surge arrester testers needs to consider testing principles, application scenarios, and voltage levels. They can be broadly categorized into four main types. These types of products differ significantly in their technical principles, functional positioning, and applicable scenarios, adapting to different levels of testing needs and forming a testing system covering the entire lifecycle of surge arresters.
I. Core Classifications of Surge Arrester Testers
(I) DC Parameter Tester (Power Outage Type, Widely Used)
The DC parameter tester is the core equipment for preventative and acceptance testing of surge arresters. Its core principle is to apply a high-voltage DC voltage to the zinc oxide surge arrester (MOA) and accurately measure the leakage current at a 1mA DC reference voltage (U₁mA) and a voltage of 0.75U₁mA, thereby determining the insulation performance and aging degree of the arrester’s varistor. This type of instrument relies on a high-precision DC high-voltage module and micro-current detection technology, possessing advantages such as high measurement accuracy, strong anti-interference capability, convenient operation, and outstanding cost-effectiveness. It is the most basic and commonly used testing equipment in power operation and maintenance.
Its core technical parameters must meet the following requirements: output voltage range 0–100kV (covering surge arresters of 10–220kV levels), current range 0–2mA (for measuring U₁mA) and 0–200μA (for measuring leakage current at 0.75U₁mA), voltage measurement accuracy ±0.5%, current measurement accuracy ±1%, and it must also be equipped with overvoltage and overcurrent protection and high-voltage audible and visual alarm functions to ensure safety during power outage testing. The limitation of this type of instrument is that it must be operated without power, and it cannot achieve real-time online monitoring of the equipment’s status. It is mainly suitable for preventative testing, acceptance testing, and post-overhaul testing of surge arresters in 10–220kV substations.
(II) AC Live-Line Tester (Online Type, Mainstay of Uninterrupted Power-Off Testing)
With the promotion of condition-based maintenance, AC live-line testers have become core equipment for online inspection and defect screening of surge arresters. Their core principle is to separate the resistive component (Ir) and capacitive component (Ic) of the leakage current under the normal operating voltage of the surge arrester through high-speed sampling, digital filtering, and Fourier harmonic analysis technology, while simultaneously detecting the 3rd to 7th harmonic content, thereby identifying aging, moisture absorption, and internal defects in the surge arrester. Resistive current, as a key indicator reflecting the performance of the surge arrester’s varistor, can effectively predict early deterioration problems through its changing trend. Capacitive current, determined by the inherent capacitance of the surge arrester, remains relatively stable. The synergistic analysis of these two components is the core logic of live-line testing.
Currently, mainstream AC live-line testers generally adopt wireless sampling technology, equipped with wireless current clamps on the high-voltage side. This eliminates the need for climbing poles and wiring, ensuring safety and efficiency, and is suitable for online testing of 6-500kV surge arresters without counters. Its core technical characteristics lie in its anti-interference capability and measurement accuracy. Through digital filtering, harmonic suppression, and inter-phase interference compensation algorithms, it can effectively suppress the influence of on-site electromagnetic interference on test results, making it particularly suitable for side-phase MOA detection in complex electromagnetic environments. Key parameters must meet: full current measurement range of 0–10mA, resistive current resolution of 1μA, voltage measurement accuracy of ±0.5%, support for waveform display, data storage, and on-site printing; some high-end models also feature AI diagnostics and remote data transmission capabilities. The limitation of this type of instrument is its susceptibility to significant on-site interference; test results need to be analyzed comprehensively based on historical data and environmental conditions. It is mainly suitable for live-line testing and condition-based maintenance of surge arresters in 35–500kV substations and transmission lines.
(III) Discharge Counter Tester (Calibration Type, Specialized Testing Equipment) As an auxiliary monitoring component of surge arresters, the reliability and accuracy of the discharge counter directly affect the timeliness of arrester fault diagnosis. The discharge counter tester is specifically designed to verify the performance of this component. Its core principle is to output an 8/20μs standard impulse current (common specifications 100A/500A) to simulate the discharge process of the surge arrester when struck by lightning, thus testing the counter’s response speed and counting accuracy.
These instruments are small and portable, often powered by a built-in lithium battery. A single charge can complete at least 50 calibration operations. The operation is simple, requiring no complex wiring. They are mainly suitable for the periodic calibration of discharge counters for surge arresters of various voltage levels, especially before the rainy season, enabling rapid troubleshooting of counter faults and ensuring that the surge arrester’s discharge status is monitorable and traceable.
(IV) Lightning Protection Component Tester (Low-voltage type, suitable for low-voltage scenarios) The lightning protection component tester is mainly for lightning protection components (such as varistors, discharge tubes, etc.) in low-voltage power distribution systems and weak current systems. Its core principle is to apply a low-voltage DC voltage and measure key parameters such as the varistor voltage and leakage current of the component to determine whether the performance of the lightning protection component meets the standards. This type of instrument has a small measuring range, moderate accuracy, and is easy to operate. It is mainly suitable for testing lightning protection components in low-voltage power distribution projects, communication base stations, smart homes, and other scenarios. It is a dedicated device for the acceptance and maintenance of low-voltage lightning protection systems.
II. Application Scenarios of Surge Arrester Testers (Full Lifecycle Coverage) The application of surge arrester testers covers the entire lifecycle of surge arresters, including production, installation, operation and maintenance, and fault diagnosis. Different types of instruments correspond to different application scenarios. Based on power system operation and maintenance specifications and actual needs, they are mainly divided into five categories to ensure the full controllability of surge arresters from factory to decommissioning.
(I) Acceptance Testing Newly installed, overhauled, or replaced surge arresters must undergo acceptance testing to establish an initial performance baseline, providing a basis for comparison in subsequent operation and maintenance. This scenario primarily uses a DC parameter tester, with core test items including insulation resistance, U₁mA, and leakage current at 0.75U₁mA, ensuring the surge arrester’s installation quality is up to standard and its performance meets design requirements. Test data must be archived and filed as fundamental data for the equipment’s entire lifecycle management. Especially in key projects such as new energy power plants and ultra-high voltage projects, the standardization of acceptance testing directly determines the safety of subsequent equipment operation.
(II) Preventive Testing (Power Outage) Preventive testing is a core aspect of power equipment operation and maintenance. According to DL/T 596-2017 “Preventive Testing Regulations for Power Equipment,” 10kV surge arresters should undergo a power outage preventive test every 1-3 years, and 35kV and above surge arresters should undergo one every 1-2 years. This scenario primarily utilizes DC parameter testers. Some high-end substations will combine data from AC live-line testers for comprehensive evaluation. The core test items are consistent with the handover and acceptance tests, focusing on comparing historical data to determine the performance trend of surge arresters and promptly identifying potential defects such as aging and moisture absorption to prevent the escalation of faults. According to industry statistics, preventative testing can effectively reduce the failure rate of surge arresters by more than 30%, making it an important means of ensuring the safe operation of the power grid.
(III) Live-line Testing (Uninterrupted Power Supply Inspection) Live-line testing does not require power outages and does not affect the normal power supply of the grid. It is the core testing method under the condition-based maintenance mode, mainly using AC live-line testers. According to operation and maintenance specifications, live-line testing is conducted 1-2 times per year, focusing on before and after the rainy season. The core purpose is to quickly screen for defects such as moisture absorption, aging, and contamination in surge arresters, and to achieve early warning by monitoring the changing trend of resistive current. For example, during the annual inspection of a 500kV hub substation in Central China, an AC live-line tester detected an abnormal increase in the resistive current and third harmonic component of a surge arrester. Combined with infrared thermography, it was determined that the surge arrester was in the early stages of aging, and a focused monitoring strategy was implemented in a timely manner, preventing a fault from occurring. Furthermore, in new energy scenarios such as wind farms and photovoltaic power stations, live-line testing can be combined with data analysis software to generate performance change curves, providing maintenance personnel with intuitive status assessment data.
(IV) Fault Diagnosis and Condition-Based Maintenance When a surge arrester is struck by lightning, experiences an online monitoring alarm, or exhibits abnormal infrared thermography, a surge arrester tester is required for specialized fault diagnosis. Combining data from DC parameter testing and AC live-line testing, the type and extent of the defect can be identified. For example, after a lightning strike, a DC parameter tester can be used to detect changes in U₁mA and leakage current to determine if the valve plate is damaged; during an online monitoring alarm, an AC live-line tester can be used to analyze the resistive current harmonic content to determine if there is moisture or aging. This scenario requires combining test data from various types of instruments to comprehensively assess the surge arrester’s condition, providing a scientific basis for condition-based maintenance, avoiding blind power outages for repairs, and improving operation and maintenance efficiency.
(V) Factory and Scientific Research Testing During the surge arrester production process, routine factory tests and type tests must be conducted using testing instruments to ensure that product performance meets national standards and industry specifications. This primarily utilizes DC parameter testers, AC live-line testers, and specialized testing equipment. Test items cover U₁mA, leakage current, harmonic analysis, etc., ensuring that each product is qualified for shipment. Research institutions can use high-precision surge arrester testers to conduct research on surge arrester varistor characteristics and aging mechanisms, providing data support for surge arrester product upgrades and technological innovation. With the development of industry technology, high-end testers have been gradually applied to research on cutting-edge technologies such as intelligent diagnostic algorithms and digital twins.
Post time: Apr-27-2026