Power and distribution transformers belong to the most important and most cost-intensive equipment of electrical power transmission and distribution. Therefore, the operation of transformers must guarantee a continuous and error-free power supply over decades.
Instrument transformers are important electrical equipment used to isolate or transform high voltages and high currents to safe values for operation or metering purposes.
Whether it’s for quality assurance testing following production or routine testing of your transformers, HVT has a solution for you.
Available Transformer Test Equipment
Frequently Asked Questions
What are the critical diagnostic tests performed on power transformers?
Comprehensive power transformer testing involves a suite of electrical diagnostics to evaluate structural, magnetic, and insulation integrity.
The primary testing routines include:
✅Loss Measurements: Verifies the no-load and load losses to determine the total losses of a transformer.
✅Transformer Turns Ratio (TTR) & Phase Displacement: Verifies winding voltage ratios and identifies shorted turns.
✅Winding Resistance Measurement (WRM): Detects loose internal connections, broken strands, or contact degradation.
✅Insulation Diagnostics: Evaluates the health of liquid and solid insulation via Power Factor/Dissipation Factor (tan delta) and Partial Discharge (PD) analysis.
✅Frequency Response Analysis (FRA): Identifies physical winding movement or core deformation caused by mechanical stress or short circuits.
What specialized transformer test sets does HV TECHNOLOGIES supply?
HV TECHNOLOGIES provides advanced, high-precision instruments manufactured by HAEFELY and Tettex, designed for both field maintenance and factory testing bays. Key specialized systems featured include:
✅HAEFELY WA 2293: An all-in-one, multi-functional transformer test set that combines winding resistance, turns ratio, and demagnetization in a single unit. It can be further upgraded to include magnetic balance, dynamic resistance, short-circuit impedance, and heat run tests.
✅TMS 600: A highly accurate, dedicated transformer loss measurement system.
✅DTTS: Turn-key solution for distribution transformer testing with low power, dielectric and quality measurements. Complete turn-key distribution transformer test system supporting all routine tests according to IEEE and IEC standards.
Why is transformer core demagnetization necessary before testing?
High residual magnetism can remain in a transformer’s magnetic core after a sudden shutdown, trip, or winding resistance test using direct current (DC). This residual flux can cause massive inrush currents upon re-energization or distort subsequent diagnostic tests like FRA and turns ratio. Advanced test systems like the HAEFELY 2293 feature built-in automatic demagnetization routines to safely normalize the core before further measurement.
How does a multi-functional test set improve field testing efficiency?
Multi-functional test sets like the HAEFELY 2293 streamline testing by allowing technicians to connect to all transformer bushings simultaneously. A true “one-time connection” setup eliminates the safety hazards and time-consuming process of repeatedly climbing the transformer to switch heavy leads between turns ratio, resistance, and vector group verification tests.
What instrumentation is used for transformer insulation and dissipation factor (tan delta) testing?
To evaluate insulation degradation, moisture ingress, and aging in transformer windings and high-voltage bushings, HV TECHNOLOGIES offers the MIDAS micro 2883. This is a portable all-in-one system combining a 12 kV power supply, a precision capacitance and dissipation factor measuring bridge, and reference standard capacitors to measure dielectric loss with extreme accuracy, even in high-interference substation environments.
Does HV TECHNOLOGIES offer complete, automated transformer test bays for manufacturing facilities?
Yes. Beyond portable field instruments, HV TECHNOLOGIES provides fully integrated, customized transformer test systems for factory routine and type testing. These automated test bays consist of state-of-the-art electronic power supplies and control software to ensure seamless compliance with IEEE C57 and IEC 60076 standards.
How can I request technical support, software updates, or a quote for transformer test equipment?
You can request customized product data sheets, system configurations, or a pricing quote by submitting the inquiry form on the Transformer Testing page. For immediate technical consultation regarding HAEFELY / Tettex transformer testing solutions, you can contact our corporate office in Manassas, Virginia, by phone at (703) 365-2330 or via email at hvsales@hvtechnologies.com.