Wuhan UHV Electric Power or equivalent domestic professional brand of oil-immersed or dry-type test transformers is the best choice
Reliable grounding: The test transformer casing, control box, test object, and voltage divider base must be connected to a common ground point, and the grounding resistance should be <4Ω. This is the lifeline for safety. Zero-position start: The power must be connected only when the voltage regulator is at zero position; it is strictly forbidden to close the switch with voltage. Safety distance: The high-voltage lead must maintain a sufficient safety distance from the test object, surrounding objects, and personnel (refer to DL 408 safety regulations), and set up fences and warning signs with dedicated supervision. Discharge operation: Before the test: Confirm that the test object is fully discharged. After the test: First discharge through a discharge rod (with resistance), then directly ground and discharge, and only then can the wiring be removed. It is strictly forbidden to touch the high-voltage end directly with hands. Environmental requirements: Avoid outdoor tests in thunderstorms, heavy fog, or humidity >85%. Oil-immersed transformers must be left to stand for more than 24 hours after transportation before powering on (to eliminate bubbles). Abnormal handling: If during the test the voltmeter pointer swings violently, the ammeter rises sharply, or the test object emits discharge sounds or smoke, immediately reduce voltage and cut off power, and investigate the cause. 7. Typical application scenarios New equipment commissioning test: Verify whether the insulation of newly installed transformers, switches, and cables is qualified. Preventive test: According to DL/T 596 regulations, regularly assess the insulation strength of operating equipment. Post-overhaul verification: After equipment maintenance or component replacement, confirm the insulation recovery. Scientific research and teaching: Universities and research institutes conduct high-voltage technology experiments. Summary and recommendations: For most power supply companies, engineering companies, and industrial and mining enterprises, Wuhan UHV Electric Power or equivalent domestic professional brands of oil-immersed or dry-type test transformers are the best choice. They have mature technology, high cost performance, and fast after-sales response. If mainly used indoors and with fire protection requirements, choose dry-type. If mainly used outdoors and pursuing cost performance, choose oil-immersed. If frequent movement, high altitude, or ultra-high voltage testing is required, choose gas-insulated. If the test object is long cables or large-capacity generators, be sure to consider configuring a series resonance withstand voltage device rather than simply increasing the capacity of the test transformer.
