IDAX Actual Testing - Hunan Province, Shaping 500kV No.1 and 2 Main Transformer Bushing
With the increasing scale of power grids and the increasing number of power equipment, the operation status of the equipment has become a key concern for the operation and maintenance department. For power transformers, high-voltage bushings, current transformers, etc., which are oil-paper insulated equipment, the aging of their internal oil and the moisture state of the oil paper have a great impact on the insulation performance, even affecting their entire life cycle.
As a key component of power transformers and circuit breakers, the reliability of high-voltage bushings has an important impact on the safety and stability of the power grid. The frequency domain spectroscopy (FDS) method of dielectric response has the characteristics of strong anti-interference ability and non-destructive, which can reflect the internal oil aging and oil paper moisture state of oil-paper insulated equipment more sensitively and comprehensively.
Kanggaote was invited by Hunan Provincial Overhaul Xingsha Training Base to test the No.1 and No.2 main transformer bushing of Shaping 500kV substation of Hunan Provincial Power Company from Oct. 18 to 19, 21.
Test Difficulties
The electromagnetic environment of the substation is complex, with a large number of frequency interference signals, and at low temperatures, making it difficult to perform accurate diagnostic analysis of the dielectric loss results.
The test was conducted using IDAX on the bushing. For low temperature effects, IDAX comes with analysis software that changes the geometry of the solid and liquid insulation to simulate each possible design and uses the Arrhenius formula to calculate and compensate for the effect of temperature on the material.
At the same time for the complex environment of a large number of electromagnetic interference, IDAX optional professional high-voltage amplifier, the perfect solution to the problem.
Test Results
In this test, it can be seen from the test data of No. 1 main transformer bushing that the data of No. 1 main transformer bushing meets the standard. IDAX's professional analysis software can calculate the water content of transformer and bushing insulation paper and dielectric loss of insulating oil based on the dielectric spectrum curve, and at the same time, through the temperature compensation function, more accurate data can be obtained. This enables timely detection of bushings at the early stage when aging occurs.
IDAX adopts dielectric frequency response method, from 1mHz to 1kHz frequency test, through 50hz, 15hz two international standards and megger through years of experience derived from the 1hz standard, to multiple judge the health degree of the bushing. Compared with the traditional 50 Hz single discriminatory method of industrial frequency dielectric loss, the dielectric frequency response can effectively exclude the measurement error (data fluctuation) brought by interference and low temperature environment to the maintenance test work, and improve the effectiveness and accuracy of bushing insulation aging diagnosis.
This 500KV UHV bushing test has achieved the expected results. Later, when conditions are available, FDS dielectric spectrum analysis can be performed on key bushing to form a perfect tracking report.
