Super Fully Automatic Distribution Transformer Test System | Factory Testing for Three-Phase Dry-Type and Oil-Immersed Transformers

I. Project Overview

Tianjin Pinggao Intelligent Electric Co., Ltd. is a wholly-owned subsidiary of Henan Pinggao Electric, under China Electric Equipment Group and the State Grid industrial system. It is Pinggao Group's core intelligent manufacturing base for the medium and low voltage distribution network sector. The company primarily engages in R\&D, production, and O\&M of 126 kV and below vacuum interrupters, high- and low-voltage switchgear assemblies, and new energy electrical equipment. Its 126 kV vacuum interrupter technology has reached the internationally advanced level and is widely used in power grid transmission and distribution projects.

In 2026, Nanke Electric successfully delivered the super fully automatic distribution transformer test system for its 13th project to Tianjin Pinggao.The system is adapted for batch factory inspection of three-phase dry-type and oil-immersed distribution transformers at the plant, covering factory tests of large-capacity, high-voltage transformers, and realizing automated testing procedures, digital data, and integrated testing.

II. Maximum Test Capability

1. Routine Test Station Parameters

(1) Three-phase, capacity \≤ 12,500 kVA, high voltage 35 kV, low voltage 0.4\–2 kV, impedance voltage 4%\–14%

(2) Three-phase, capacity \≤ 3,000 kVA, high voltage 10 kV, low voltage 0.4\–2 kV, impedance voltage 4%\–8%

2. Routine Station Description

Suspended outgoing line type. One-time wiring test, automatic switching of test items, completing 7 routine tests.

When the low-voltage side current at the routine station exceeds 4,000 A, the load test requires manual installation of the low-voltage side load short-circuit bar before proceeding.

3. Temperature Rise Test Station Parameters

(1) Thre-phase, capacity \≤ 12,500 kVA, high voltage 35 kV, low voltage 0.4\–2 kV, impedance voltage 4%\–14%

(2) Three-phase, capacity \≤ 3,000 kVA, high voltage 10 kV, low voltage 0.4\–2 kV, impedance voltage 4%\–8%

4. Temperature Rise Station Description

Suspended outgoing line type is adopted. Manual wiring per test item to complete the full set of temperature rise\–related tests.

III. Test Items

1. Routine Test Station

One-time wiring test, automatic switching of test items, completing 7 routine tests:

(1) Insulation resistance measurement

(2) DC resistance measurement

(3) Turns ratio group measurement

(4) Transformer no-load loss and no-load current percentage test

(5) Transformer load loss and short-circuit impedance test (\≥ 50% rated current)

(6) Transformer induced withstand voltage test

(7) Transformer AC withstand voltage test

2. Temperature Rise Test Station

Manual wiring test per item:

(1) Temperature rise test (performed at the temperature rise station)

(2) Partial discharge measurement (performed in a noise-shielded room)

(3) Noise measurement (performed in a noise-shielded room)

IV. Project Highlights

(1) Super fully automatic integrated production line testing

The routine station achieves suspended one-time automatic wiring, eliminating the need for repeated wire disconnection and reconnection. One-click automatic switching of 7 factory tests significantly reduces the testing time per transformer and is suitable for large-volume factory inspection production lines.

(2) Full-range wide compatibility

One set of equipment simultaneously covers two mainstream three-phase dry-type and oil-immersed distribution transformer specifications: 10 kV/35 kV, 3,000 kVA/12,500 kVA, with impedance voltage compatibility in the 4%\–14% range, meeting the requirements for transformer factory inspection.

(3) Multi-dimensional high-precision test support

Equipped with Yokogawa WT500 power analyzer, TWPD-2C four-channel digital partial discharge comprehensive analyzer, together with a professional noise-shielded room, it can simultaneously complete high-precision multi-dimensional testing of losses, partial discharge, noise, and temperature rise. The test accuracy meets the State Grid factory test standards.

(4) Customizable factory test reports on demand

Report templates can be customized according to State Grid acceptance requirements. All test data is automatically aggregated throughout the entire process, and paper/electronic files can be exported with one click, meeting the requirements for factory quality traceability management.

V. Commissioning Information

Commissioning time: July 2026