2000A High Current Generator
It is a special equipment specially designed and manufactured for electrical equipment tests in power departments and factories and mines, such as current transformer and other electrical equipment current load tests, temperature rise tests, and testing the maximum breaking current and breaking capacity of switches. This series of products has a split/integrated structure, with features such as infinitely adjustable output current, balanced current rise, wide load variation range, reliable operation, simple operation, and safety. The 2000A high current generator is an ideal equipment for current rise or temperature rise tests in industrial and mining enterprises.
Functional Features of 2000A High Current Generator
1. This fully automatic 2000A high current generator adopts touch screen control with a full Chinese interface.
2. The 2000A high current generator is equipped with a built-in micro printer, which can print relevant test data. It has a high degree of automation and is easy to operate.
3. Before the test, parameters such as test current and time can be set as needed.
4. The 2000A high current generator automatically raises the current, and the color large screen displays the output current in real time. When the set current is reached, timing starts.
5. After timing is completed, the current is reduced, automatically reset to zero, and the main circuit trips. Turn off the air switch, and the test ends.
I. Basic Requirements for Temperature Rise Test of 2000A High Current Generator
(1) In order to ensure accurate measurement data in the temperature rise test, the accuracy of the meters used to measure stator electrical quantities should not be lower than 0.5 level, and those for measuring rotor should not be lower than 0.2 level.
(2) The temperature rise test of the generator with the 2000A high current generator is a long-term thermal stability test. Each load test requires the rotor current to remain stable, with a variation range not exceeding 1% of the test current; the stator voltage, current, and power should also be kept as stable and three-phase balanced as possible, with a variation range not exceeding 3% of the test value. For this reason, the automatic voltage regulator should be removed during the test, and the power factor should be maintained at the rated value.
(3) During the test with the 2000A high current generator, the cooling medium temperature should be at or close to the rated value. Under each test load, the temperature change of the cooling medium should not exceed 1K.
During the test, under each load, after stabilizing for 1 hour, measure each measured electrical quantity and temperature every 15 or 20 minutes until stable. The so-called thermal stability means that the temperature change of each part of the motor within 1 hour does not exceed 2K. The time required to reach thermal stability depends on the type and capacity of the motor, generally about 3-4 hours.
II. Preparations Before the Temperature Rise Test of 2000A High Current Generator
(1) Familiarize with Technical Data of 2000A High Current Generator
Before the test, test personnel should be familiar with the instructions and relevant technical data provided by the electrical equipment manufacturer, especially to clarify the winding insulation structure, insulation level, allowable temperature (temperature rise) values for each part, operating conditions, and the embedding positions of temperature measurement elements.
(2) Develop Test Plan for 2000A High Current Generator
Based on the mastered situation, jointly negotiate with relevant technical personnel of the power plant to formulate the temperature rise test plan for the 2000A high current generator.
(3) Measure DC Resistance of Stator and Rotor Windings of 2000A High Current Generator
When conducting the generator temperature rise test with the 2000A high current generator, the cold-state DC resistance of the generator stator and rotor windings is very important basic data in the temperature rise test. This is because when measuring the average temperature of the stator and rotor windings under power, the cold-state resistance is used as the reference value to convert the average winding temperature, so its measured value directly affects the accuracy of the temperature rise test. Therefore, the DC resistance value should be accurately measured before the test with the 2000A high current generator.
The neutral point disconnecting switch of the 2000A high current generator is in the closed position, that is, the transformer neutral point is grounded and operating. At this time, zero-sequence overcurrent protection should be put into operation; when the neutral point disconnecting switch of the transformer is in the open position, that is, the transformer neutral point is not grounded and operating, at this time, zero-sequence overvoltage protection and gap discharge zero-sequence overcurrent protection should be put into operation.
Actual operation shows that this protection has withstood the test in power grids at all levels, without misoperation or refusal. At the same time, this protection method is basically adopted in modern power grid design.
