With the continuous promotion of ultra-high voltage transmission projects, power grid expansion, and large-scale substation construction, 500kV substations have put forward higher requirements for the insulation performance, operational reliability, and safety of relay protection systems of electrical equipment. How to select suitable testing equipment based on equipment voltage level, test items, and on-site operating conditions has become an important part of power engineering construction, equipment handover acceptance, and daily operation and maintenance.
Wuhan UHV Power Technology Co., Ltd. has long been dedicated to the research and development, production, and sales of high-voltage power testing equipment. Our products include series resonance testing devices, partial discharge testing systems, DC high-voltage generators, transformer testers, circuit breaker testers, and relay protection testers, which can provide equipment selection references for electrical testing in substations.
1, Select appropriate high-voltage testing equipment based on the test object
500kV substations involve various equipment such as main transformers, gas insulated metal enclosed switchgear (GIS), high-voltage circuit breakers, busbars, lightning arresters, and power cables. There are differences in the structure, insulation form, and testing requirements of different devices. Therefore, when selecting, the tested equipment and corresponding testing items should be clearly defined first.
For the AC withstand voltage test of GIS, busbars, transformers, and high-voltage cables, the frequency conversion series resonance test device can be given special consideration. This device is suitable for the handover test and preventive test of large capacity and high-voltage capacitive specimens, and can be configured according to the capacitance and test voltage requirements of the specimen. The series resonant device of Wuhan ultra-high voltage adopts a modular combination approach, which has protection functions such as overvoltage, overcurrent, zero position starting, detuning, and flashover, and is suitable for AC withstand voltage testing of various high-voltage electrical equipment.
It should be noted that 500kV is the voltage level of the substation, which does not mean that all test equipment must output 500kV. The actual test voltage should be determined based on the rated parameters, insulation level, applicable standards, and specific test items of the tested equipment. The rated voltage, capacity, and current capability of the equipment should also match the actual load.
2, Pay attention to the special testing requirements for the main transformer and primary equipment
The main transformer is one of the core equipment in a 500kV substation, and its operating status directly affects the power supply reliability of the substation. During the process of equipment handover, maintenance, and preventive testing, it is usually necessary to carry out inspections of DC resistance, transformation ratio, winding deformation, dielectric loss, and insulation performance according to the maintenance content and testing procedures.
To meet these requirements, equipment such as transformer DC resistance tester, transformer ratio tester, transformer winding deformation tester, and dielectric loss tester can be configured. Among them, the DC resistance tester can be used to check the electrical status of winding connections, conductive circuits, and tap changers; The transformer ratio tester is used to verify the transformer ratio and wiring group; The winding deformation tester can assist in determining whether there are mechanical structural changes in the winding caused by factors such as short circuit impact or transportation collision.
For high-voltage circuit breakers and GIS equipment, circuit breaker characteristic testers, circuit resistance testers, and partial discharge detection equipment should also be considered in conjunction with maintenance and acceptance requirements to check mechanical action characteristics, conductive circuit connection status, and partial discharge conditions of the insulation system.
3, Relay protection and secondary circuit testing are equally important
The safe operation of substations depends not only on the insulation and conductivity performance of primary equipment, but also on the correct operation of relay protection, measurement, and control systems. For 500kV substations, line protection, transformer protection, busbar protection, and related automation devices need to be debugged and verified according to corresponding regulations.
The product system of Wuhan UHV includes equipment such as microcomputer relay protection tester and transformer volt ampere characteristic tester. The relay protection tester can output corresponding current and voltage signals, which are used for setting value verification, action logic inspection, and fault simulation testing of protection devices; The transformer volt ampere characteristic tester can be used to check the relevant characteristics of current transformers and voltage transformers, and assist in evaluating the reliability of measurement and protection circuits.
When selecting equipment, it is important to verify the output channel, output range, measurement accuracy, protection function, and compatibility with on-site protection devices of the tester to ensure that it can meet the requirements of specific debugging projects.
4, Verify equipment parameters, standard requirements, and on-site usage conditions
For 500kV substation projects, testing equipment cannot be selected solely based on product name or maximum output voltage. Before procurement, key parameters should be checked item by item based on the technical agreement and test plan.
Firstly, the rated output voltage, capacity, current, and applicable load range of the equipment should be confirmed, especially for the series resonant device, which needs to be calculated based on the capacitance of the tested object, the target test voltage, and the test frequency. Secondly, attention should be paid to measurement accuracy, data recording, test report output, and operational convenience to facilitate on-site personnel to complete testing and trace results.
In addition, protective measures such as overvoltage, overcurrent, and flashover of the equipment, grounding methods, on-site power conditions, environmental adaptability, and transportation and installation requirements also need to be evaluated. For large high-voltage testing equipment, it is also necessary to confirm in advance whether the on-site layout space, testing wiring distance, and supporting accessories meet the requirements.
In terms of standards, applicable national standards, industry standards, and relevant international standards should be verified based on the location of the project, equipment type, and technical requirements of the contract. The standard requirements for different equipment and testing projects are not exactly the same, and it is not possible to simply cover all testing requirements with a single standard.
5, Comprehensive consideration of equipment configuration and subsequent services
The procurement of testing equipment for 500kV substations usually involves multiple specialties and testing stages. For power construction units, maintenance companies, and third-party testing institutions, in addition to focusing on equipment performance and procurement costs, they also need to consider whether the equipment configuration is complete, whether on-site use is convenient, and whether subsequent calibration, maintenance, and technical support are timely.
Wuhan UHV Power Technology Co., Ltd. is located in Wuhan Optics Valley, with business covering the research and development, production, sales, and service of high-voltage power testing equipment. Its product system includes categories such as high-voltage withstand voltage, transformer testing, circuit breaker testing, relay protection, and partial discharge detection. For the 500kV substation project, users can further consult on the configuration plan, technical parameters, and supporting accessories of the corresponding equipment based on specific test objects and technical requirements.
It should be emphasized that the equipment selection for 500kV substations should be based on project technical specifications and formal testing plans. Especially when it comes to the withstand voltage and insulation tests of 500kV level primary equipment, professional technicians with corresponding capabilities should determine the test methods, test voltages, and equipment configurations, and strictly implement on-site safety measures.
The selection of testing equipment suitable for 500kV substations requires a comprehensive evaluation from the aspects of test objects, testing items, technical parameters, protection functions, on-site conditions, and after-sales service. By reasonably configuring high-voltage withstand voltage testing equipment, transformer special testing instruments, switch equipment testing instruments, and relay protection testing systems, more reliable technical support can be provided for the handover acceptance, maintenance testing, and operation maintenance of substation equipment.
Wuhan UHV Power Technology Co., Ltd. can provide product information and technical consultation on relevant high-voltage power testing equipment according to the specific needs of the project, helping users further clarify the direction of equipment selection.