Low and Medium Voltage Switchgear Testing？

What are  Low and Medium Voltage Switchgears?

Low-voltage switchgear ‌refers to the electrical device with a rated voltage of 1000V or below, which is mainly used in the power distribution and control system of homes, commercial buildings and other places. Common low-voltage switchgear includes distribution cabinets, junction boxes, circuit breakers, and switches. These devices are usually made of conductive materials such as copper and aluminum, and are equipped with appropriate protective devices to ensure safety and reliability‌.

Medium voltage switchgear ‌refers to the electrical device with a rated voltage between 1kV and 35kV, which is usually used in power transmission and distribution systems in industry, agriculture, energy and other fields. Medium voltage switchgear includes isolation switch, load switch, circuit breaker, substation, etc. Its main characteristics are large power, strong carrying capacity, stable operation‌.

Low Voltage Switchgear

Low and Medium Voltage Switchgear Testing？

Low voltage switchgear test

Preparation stage:

Make a test plan: Make clear the test purpose, test content, test method, test time, test personnel, etc.

Prepare test equipment: Including all kinds of electrical test equipment, mechanical test equipment, etc.

Appearance inspection stage:

Inspect the appearance of the low-voltage switchgear, including the structure, size, material, etc., to ensure that it meets the relevant standards and user requirements.

Performance test phase:

· Electrical performance test: Including rated current, rated voltage, operation times, transmission system test, insulation resistance, voltage resistance, contact resistance and other test items. These tests ensure that the low-voltage switch works properly under a variety of conditions and assess its electrical safety.

· Mechanical performance test: Including operating force, operating stroke, locking device and other test items to evaluate the mechanical performance and durability of the low-voltage switch.

Temperature rise test phase:

By installing a temperature sensor on the device, the temperature rise of the device under different loads is measured to evaluate its heat dissipation performance and service life.

Reliability test phase:

By simulating the actual use environment and conditions of use, the equipment is used for a long time and high frequency to evaluate its reliability and stability.

Protection level test phase:

The waterproof, dustproof and other characteristics of its shell are tested to assess whether its protection level meets the requirements.

In addition, CB certification of low-voltage switchgears also covers the testing of dimensions and marks to ensure that they meet the requirements of the standard and avoid installation and application problems caused by product dimensions that do not meet the specifications.

Medium Voltage Switchgears

Medium voltage switchgear test

Pre-test check:

· Check whether the push and pull of the hand car is flexible and light, without blocking and collision phenomenon.

· Check whether the grounding contacts between the hand car and the cabinet are in close contact.

· Measure the ground continuity of the medium voltage switchgear.

Insulation resistance test:

Use an insulation resistance tester to measure insulation resistance, including circuit breakers, transformers, and busbars.

Conductive circuit resistance test:

Use the circuit resistance tester to measure the resistance of the conducting circuit, including circuit breakers, bus bars and other components.

Environmental verification test:

· Wet heat test: Verify whether the equipment can work normally under the influence of wet heat. The test conditions include specified temperature, humidity and duration. After the test, the insulation resistance measurement and performance test were carried out.

· Dry heat test: Verify whether the equipment can work normally under the influence of high temperature. During the test, the switchgear should be operated at the rated operating voltage and frequency, and held at the specified temperature for a certain time before the functional test.

· Low temperature test: Verify that the switchgear can operate normally under low temperature conditions. The equipment is tested in the state of power failure, and the function test and insulation resistance measurement are carried out after holding it at a specified low temperature for a certain period of time.

Vibration test:

Install the switchgear on the vibration table according to the actual running state, and connect the working power supply. Vibration resistance test and vibration resistance test of resonant frequency points are carried out. The switchgear should work properly during and after the test.

Tilt and sway tests:

The switchgear is installed on the tilt and sway test equipment according to the actual use state, and the working power supply is connected. Dynamic swing test and tilt test were carried out. Functional tests are carried out before during and after the test.

Protection test:

The actual process test of overcurrent protection and circuit breaker operation is carried out, including calculation of cutting fault time and error analysis. Ensure that the circuit breaker is able to cut off the faulty circuit correctly and quickly.