High Voltage Testing & Diagnostics

About High Voltage Testing & Diagnostics Equipment

High voltage systems require specialist testing devices to carry out maintenance. Conventional test equipment is generally made for use on lower voltage systems, so is unsuitable for safe usage on HV installations.

Live high-voltage lines in particular must be tested using correctly earthed and insulating equipment that ensures that the user won't receive extremely powerful electrical shocks. Live line testers come in various forms ranging from smaller devices up to long poles designed for hooking onto HV systems without the need to use insulating ladders and other equipment.

These devices work by using an insulated pole attached to an indicator that alerts the user to the presence of voltage on a system. As the device is insulated and earthed the flow of electricity will not pass down the tester and into the person holding it, instead returning safely down to earth. Live line testers are also compatible with specific adapters known as bent-end adaptors. These are used for direct connection to switchgear or similar applications and come in different angles for use on different types of equipment.

It is of the utmost importance that insulated live line testers are regularly checked for efficiency via the use of a high-voltage proving unit. These devices should be used both before and after testing to ensure that the live line tester is working correctly and its generated result values are not outside the norm. Proving units such as those on the site are ideal for this purpose.

Phase comparators are also used commonly on high voltage systems, allowing the user to compare phases by the use of dual-pole devices that are made for attachment to the HV system under test. Like live line testers, these can generally be hooked onto overhead lines, switchgear, and other applications and indicate phase either via visual indicators or by the use of analogue meters attached to the rod.

Popular Products

BAUR PGK25 DC High Voltage Tester: Portable device for testing up to 25 kV. It offers two adjustable voltage ranges (0-5 kV and 0-25 kV), an integrated ammeter with five ranges (1 µA to 10 mA), and a built-in timer for 1 to 30 minutes. Weighing 16.5 kg, it operates on a 12V rechargeable battery or external supply and is designed for testing medium-voltage networks, especially paper-insulated cables.
Metrel MI3295M Step Contact Voltage Meter: Tests protective earthing in power systems. It features noise immunity for accurate step and contact voltage measurements (10 µV resolution), a current generation station, and supports simultaneous use of multiple voltmeters.
T&R KV50-100 mk2 High Voltage AC Test Set: Outputs up to 50 kV AC and 100 mA for insulation testing. It features an oil-filled transformer and a separate control unit with precise voltage and current control, large analogue instruments, and a variable electronic trip (10% to 110% output).
Megger MIT515 5kV Insulation Resistance Tester: Versatile tool for high voltage equipment maintenance, offering test voltages from 250V to 5000V and measuring insulation resistance up to 10 TΩ. It includes Polarization Index (PI), Dielectric Absorption Ratio (DAR), and Dielectric Discharge (DD) tests, with a CAT IV 600V safety rating. Equipped with a rapid-charge lithium-ion battery, it can also operate from line power.
Chauvin Arnoux CA6545 Digital Megohmmeter: Robust insulation tester measuring from 10 kΩ to 10 TΩ. It offers four fixed test voltages (500V, 1,000V, 2,500V, 5,000V) and an adjustable range from 40V to 5,100V. With a large backlit LCD, it displays measurements and automatically measures voltage, capacitance, and residual current. Powered by a NiMH rechargeable battery, it lasts up to 30 days.
Seaward Clare HAL PowerSmart Three Phase Module: Enhances the Clare HAL104 Production Line Safety Tester, allowing load and leakage testing on three-phase equipment. It supports up to 50A per phase and 12.5kVA, offering both single and three-phase configurations for efficient and accurate testing in industrial settings.
Megger VIDAR Vacuum Interrupter Tester: Verifies vacuum interrupters in circuit breakers with a DC test voltage of 10 kV to 60 kV. Weighing 7 kg (15 lbs), it's portable for field and shop use. It features a green light for approved interrupters and a red light for defects, ensuring safe and efficient testing. Developed with industry leaders, the VIDAR enhances electrical system safety and performance.
Megger / Programma SVERKER 750 Relay Test Set: Innovative solution to secondary testing of protective relays, handling both single-phase and three-phase protection. It features a comprehensive measurement display and weighs 18 kg (39 lbs) for portability. The set can sync multiple units for three-phase testing and complies with EU safety standards.
T&R PCU1-SP mk2 Primary Current Injection Test Set: A dynamic system for primary current injection and circuit breaker testing, generating up to 5000A and 11.5kVA for 40 seconds. It features a digital timing system, a true RMS memory ammeter, and direct CT ratio readings. Rugged, portable and suitable for field and lab use,
T & R 200A-3PH MK3 Secondary Current Injection Test Set: Portable system for testing protective relays and circuit breakers, injecting up to 200A AC per phase. It features a true RMS digital meter with a 3.5-digit LED display and a 1ms resolution timing system for precise trip time measurements. With three independent, fully isolated outputs, an auxiliary 240V AC output, and electronic overcurrent protection, it ensures safety and complies with BSEN61010 standards.
Sonel MMR-650 Micro-Ohmmeter: Measures very low resistances in resistive and inductive objects, ideal for testing connections and motor windings. It performs 4-wire measurements up to 1999.9Ω with 0.1μΩ resolution and up to 10A test current. Features include temperature compensation, a robust IP54/IP67 case, touchscreen interface, and USB/WiFi connectivity.
Alber CRT-400 Cellcorder Battery Tester: Handheld battery tester for measuring cell voltage, resistance, and intercell connections on batteries from 1V to 16V. It meets IEEE standards, offers wireless and USB data transfer, and includes software for detailed analysis and reporting. Its portable, durable design is ideal for industries like power generation and telecom.

FAQs

What is high voltage testing?
To ensure electrical equipment can withstand the stresses it will face over its operational life. Key tests include dielectric strength testing to assess insulation durability, withstand testing for voltage endurance, partial discharge testing for detecting insulation defects, and impulse testing to simulate lightning strikes.
What are the types of high-voltage tests?
High voltage testing involves several critical tests for assessing electrical equipment's safety and durability. Sustained low-frequency tests evaluate dielectric strength, constant DC tests check insulation integrity, high-frequency tests simulate operational stresses, and surge tests assess resilience to extreme conditions. Each test ensures safe and reliable operation.
Why is high voltage testing important?
It is essential for ensuring the safety and reliability of electrical equipment. By exposing equipment to various voltage stresses, these tests identify weaknesses and insulation defects, ensuring it can withstand operational and environmental challenges like power surges and lightning strikes. This testing helps maintain system integrity, prevent costly downtime, and ensure compliance with industry standards, safeguarding both equipment and personnel.
How do you perform high-voltage diagnostics?
Assess electrical equipment's condition through several tests. It begins with visual inspections, followed by insulation resistance tests to ensure effectiveness. Withstand testing checks high voltage endurance, while partial discharge testing detects potential defects. Tan delta testing measures dielectric losses, helping identify issues early to ensure system reliability and safety.
How do I perform high-voltage insulation testing?
Testing includes key steps to ensure electrical equipment safety. Begin with a visual inspection for damage, then use an insulation resistance tester (megohmmeter) to measure resistance—higher values indicate better quality. Conduct a withstand test to identify weaknesses by applying high voltage for a set duration, and perform partial discharge testing to detect potential defects. Finally, record and analyze results to assess insulation condition, helping maintain reliability and ensure compliance with industry standards.
What equipment is used for high-voltage testing?
Key tools include insulation resistance testers for measuring insulation, hipot testers for applying high voltage, and partial discharge detectors for identifying defects. Voltage dividers and power supplies provide necessary testing voltage, while oscilloscopes monitor performance.
What are the safety precautions for high-voltage testing?
Safety precautions for high voltage testing are vital for protecting personnel and equipment. Ensure only trained personnel conduct tests and use appropriate PPE, like insulated gloves and safety glasses. Verify proper grounding, secure the testing area, and use insulated tools while maintaining distance from live parts. Regularly inspect equipment and follow manufacturer guidelines. These measures minimize accident risks and ensure a safe testing environment.
How often should high-voltage testing be performed?
The frequency varies based on equipment type, environment, and standards. Initial testing is required during installation, followed by regular testing as part of maintenance. Annual testing is advised for critical equipment, while harsh environments may need more frequent checks. Testing is also necessary after repairs or modifications to ensure safety and compliance.
What are common high-voltage testing methods?
Methods include sustained low-frequency tests to assess dielectric strength, constant DC tests for insulation integrity, high-frequency tests to simulate operational stresses, and surge tests to evaluate resilience against voltage spikes.
How to interpret high-voltage test results?
Interpreting high voltage test results involves analyzing insulation resistance (higher values indicate good quality), ensuring withstand tests show no failures, checking for discharges in partial discharge tests, and confirming low dielectric losses in tan delta results.
What is the difference between AC and DC high-voltage testing?
AC high voltage testing simulates operational conditions for AC systems, identifying insulation weaknesses under cyclic voltage stresses. DC testing, using direct current, is ideal for detecting insulation defects and assessing insulation quality, especially in DC systems. Both tests are essential but serve different purposes based on equipment requirements.
What are the regulations for high-voltage testing?
High voltage testing regulations by IEC, IEEE, and NEC ensure the safety and compliance of electrical equipment. They include safety standards, performance criteria, testing procedures, and documentation requirements, with periodic testing to maintain equipment integrity. Adherence prevents failures, ensures safe operation, and aligns with industry best practices.