I. Project Overview

Nanke Electric has delivered the first set of the 2026 automatic distribution transformer testing system to Zhejiang Hubei Power Technology Co., Ltd. The partner, Zhejiang Hubei Power Technology Co., Ltd., operates five major business divisions: power transformer complete sets, State Grid–standardized box-type substations, State Grid–standardized ring main units and eco-friendly cabinets, pole-mounted circuit breakers, and new energy. Its business covers both traditional transmission and distribution as well as new energy sectors. Products such as State Grid–standardized box-type substations, ring main units, eco-friendly cabinets, primary-and-secondary-integrated ring main units, primary-and-secondary-integrated pole-mounted circuit breakers, power transformers, transformer complete sets, distribution boxes, and branch boxes have all been included in the State Grid’s procurement list. In the new energy segment, it can supply integrated photovoltaic power stations, photovoltaic step-up substations, American/European/Chinese-style photovoltaic box-type substations, photovoltaic grid-connection cabinets, grid-connection boxes, AC combiner boxes, modular intelligent prefabricated cabins, and a full range of outdoor cabinet-type energy storage systems. The automatic distribution transformer testing system delivered this time is used for factory acceptance testing of the customer’s transformers. With its integrated testing capabilities, it completes tests on various performance indicators, ensuring that the customer’s transformer products meet quality standards upon leaving the factory.

II. Maximum Testing Capacity

This automatic distribution transformer testing system is compatible with multiple voltage levels and large-capacity transformers. Key parameters are as follows:

High-voltage side voltage: 10 kV, 20 kV, 35–38.5 kV

Low-voltage side voltage: 0.4 kV, 0.69 kV, 0.8 kV, 1.14 kV

Maximum equipment capacity: ≤3150 kVA

Applicable frequency: 50–60 Hz

Impedance range: 3%–8% (±10%)

III. Test Items

The system can automatically perform multiple standard performance tests on transformers. Test contents include:

(1) Measurement of no-load loss and no-load current;

(2) Calculation of no-load current percentage;

(3) Measurement of load loss and conversion to standard temperature;

(4) Measurement of short-circuit impedance and conversion to standard temperature;

(5) Induced withstand voltage test;

(6) Power-frequency withstand voltage test;

(7) Temperature-rise test;

(8) Partial discharge test.

IV. Project Highlights

(1) Self-developed integrated testing equipment, enabling automated operations

Nanke Electric independently developed the automatic distribution transformer testing system, integrating variable-frequency power supplies, power analyzers, temperature monitoring devices, and partial discharge detectors into a single unit. It can simultaneously conduct multiple tests, features an intuitive operating interface, reduces manual steps, and improves transformer testing efficiency.

(2) Automatic data processing and storage for multiple test items, minimizing human error

After completing no-load, load, impedance, and partial discharge tests, the system automatically calculates losses and converts impedance values to standard temperatures. All raw test data is stored locally, eliminating the need for manual recording and calculation, thus avoiding errors associated with handwritten data entry.

(3) Customizable test reports tailored to customer needs, adapting to different product types

Based on the specific parameters of customers’ distribution transformers or photovoltaic box-type substations, the system can configure corresponding test procedures and generate standardized test records, meeting the diverse testing requirements of customers in the transmission and distribution as well as new energy sectors.

V. Commissioning Information

This automatic distribution transformer testing system was installed, commissioned, and put into operation in May 2026. All functions and testing indicators passed acceptance, and the equipment was delivered to Zhejiang Hubei Power Technology Co., Ltd.