In the current context of accelerating the construction of new power systems, transformers, as the core equipment of transmission and distribution grids, have a direct impact on the safety and economy of grid operation in terms of detection accuracy and efficiency. However, facing the complex variety of testing equipment in the market, how to make scientific and practical selection decisions is still a practical issue faced by many power operation and procurement personnel. Based on the product practice of Wuhan UHV Power Technology Co., Ltd. and the publicly available technical information in the industry, a complete set of transformer testing equipment selection logic is gradually becoming clear.

1、 First determine the object, then determine the equipment

The first step in selection is not to compare equipment parameters, but to clarify what needs to be tested. Transformers with different voltage levels and capacities have significant differences in the functional and accuracy requirements for testing equipment. The testing focus of distribution transformers (10kV/400V) is usually concentrated on basic items such as DC resistance, transformation ratio group, insulation resistance, and no-load loss; For power transformers of 110kV and above, the dielectric loss factor (tan δ), winding deformation testing, and dynamic characteristics of on load tap changers need to be included in the mandatory testing range.

The comprehensive testing platform for Wuhan UHV transformers follows this logic in its design. The UHV-315 series can test the no-load and load characteristics of power transformers and distribution transformers, and also supports frequency doubling induction test, power frequency withstand voltage test, zero sequence impedance test, and temperature rise test. The measured voltage range covers 0.1 to 4000V, and the current range covers 0.1 to 200A, which can meet the testing needs of power transformers of 6300kVA/35kV and below. This approach of "defining functions based on objects" avoids configuring excessive testing capabilities for low-voltage devices and prevents functional deficiencies during high-voltage device detection.

2、 Integration or Modularization: Homework Scenarios

Another key decision in the selection process is whether to choose a highly integrated comprehensive testing platform or to purchase single function instruments on a project by project basis. The core value of the transformer comprehensive testing platform lies in "one-time wiring, continuous testing of multiple projects". The Wuhan UHV test bench integrates multiple detection functions such as no-load loss, load loss, transformation ratio group, DC resistance, insulation resistance, etc. on the same platform. The measurement part is controlled by PLC, and the no-load and short-circuit test data are synchronously sampled by a microcontroller, avoiding the accumulation of errors caused by traditional methods of reading voltage meters, ammeters, and power meters separately and manually calculating them the source.

The practical significance of this design is particularly prominent in maintenance scenarios. Taking the annual inspection of a 110kV substation as an example, it usually requires 3 to 5 devices such as a transformer test bench, a power frequency withstand voltage tester, and an insulation resistance meter to work together. The higher the integration level of the comprehensive testing platform, the simpler the on-site wiring, and the stronger the flexibility of equipment scheduling and personnel arrangement. In the distribution network renovation project, grouping according to voltage level and equipment type, each group is equipped with a comprehensive testing platform and a high-voltage switch characteristic tester, which has become a validated and effective parallel operation mode.

3、 Accuracy and range: uncompromising hard indicators

No matter what form of equipment is chosen, measurement accuracy and range coverage are always the bottom line of selection. In industry practice, the power accuracy of loss measurement is usually required to reach level 0.2 or higher, and the relative error of voltage and current channels generally needs to be controlled within the range of ± 0.1% reading plus ± 0.1% range. The transformer loss parameter tester for Wuhan UHV adopts high-precision voltage and current transformers combined with high-speed AD converters. Its design goal is to ensure accurate acquisition of test signals, thereby truly reflecting the energy efficiency status of the transformer.

The 'sufficient and sufficient range' is equally important. The output capacity of the power supply for no-load and load tests must be greater than the maximum no-load loss and load loss of the tested transformer, otherwise bottlenecks may be encountered in the boosting and current boosting process. When selecting, it is recommended to use the highest voltage level and maximum capacity in the list of transformers to be tested as the reference lower limit of the equipment range, rather than the upper limit.

4、 Environmental adaptation: The site is never a laboratory

If the selection of testing equipment only focuses on technical parameters, it often ignores the constraints brought by the actual working environment. When working outdoors in winter in the north, LCD screens may exhibit delayed response in environments below minus 15 ℃, highlighting the necessity of wide temperature screen models; When there is no mains power supply in the field construction site, the battery life of the equipment directly determines the effective working time per day, and backup generators or high-capacity mobile power sources become supporting options. For the grid connection testing of new energy power plants, photovoltaic scenarios require testing equipment to have measurement capabilities that can adapt to DC systems, while the testing of wind farm tower foundations and box transformers requires higher levels of protection.

Wuhan UHV has clearly marked the environmental adaptation parameters for the working temperature range of -10 to 40 ℃ and relative humidity of 30% to 90% in its product specifications, and supports multiple automatic and manual control modes. The management functions such as data storage, export, and printing are also becoming more complete. These seemingly 'non core' functions often have an impact on actual maintenance efficiency that is no less than the measurement accuracy itself.

5、 Service and Customization: Undervalued Selection Dimensions

The procurement decision of equipment should not be limited to delivery. Transformer testing equipment is a professional tool for long-term use, and calibration, maintenance, software upgrades, and technical training constitute an important part of its entire lifecycle cost. Wuhan UHV has established a full process system for localized services, including on-site site survey, equipment customization and design, installation and commissioning, and systematic training for operators. Its after-sales commitment includes 15 minute telephone guidance to troubleshoot simple faults, one-year free warranty, and other terms.

In terms of customization capabilities, the company emphasizes that the core control system, detection module, and data processing program are all independently developed, and the equipment configuration and functional modules can be flexibly adjusted according to the customer's factory layout and detection capacity. The practical value of this capability lies in the ability of the equipment to adapt through program iteration and module adjustment when the customer's testing standards are updated or production capacity is upgraded, rather than being forced to replace as a whole.

The selection decision of transformer testing equipment is shifting a single dimension of "buying a good instrument" to "building a solution that is suitable for one's own testing scenario". The integrated product route of Wuhan UHV with comprehensive testing platform as the core, as well as the service system established around domestic research and production, provide a practical reference for this transformation. For the purchaser, clearly defining the testing objects, core projects, environmental constraints, and long-term service requirements is always a prerequisite for making wise choices.