Split-type Triple Frequency Power Generator
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Split-type Triple Frequency Power Generator Principle
This product is designed to meet the requirements of the triple-frequency induced voltage withstand test and partial discharge test specified in the "Regulations for Preventive Tests of Electrical Equipment".
The induced voltage withstand test for transformers and instrument transformers is an important test to verify whether the product meets national standards. The longitudinal insulation induction test of interlayer, inter-turn, section, and phase-to-phase insulation of windings is an important item to assess whether the windings meet the requirements. In order to increase the test voltage of the windings without causing the core of the transformer or instrument transformer to saturate excessively and lead to excessive excitation current, the test frequency needs to be increased, generally to 100Hz-400Hz.
There are several methods to obtain this, among which the most applicable are: ① combination of three variable-frequency generators (100Hz-400Hz); ② combination of three single-phase transformers (150Hz), and the most convenient is the second method.
Combination method: The primary side is star-connected, and the secondary side is open-delta connected. When the core is not saturated, the main flux it produces must be a flat-topped wave. Since the main flux of the flat-topped waveform contains a large component of the third harmonic magnetic energy Φ3, and the frequency of the third harmonic flux f3=3f1, the main flux induces a third harmonic phase electromotive force.
Due to the star connection on the primary side and the open-delta connection on the secondary side, the core operates in a saturated state, and the no-load current I is a peaked wave. In addition to the fundamental wave, it also contains higher harmonics. Among the higher harmonics, the amplitude of I is relatively large. Since the secondary side is open, the three-phase fundamental components cancel each other out, leaving only the third harmonic output.
It utilizes the saturation characteristics of the magnetic circuit to extract the third harmonic voltage with the largest component among the harmonics as the power source of the generator, and performs frequency-doubling and voltage-doubling tests on inter-turn, inter-section, and interlayer insulation of inductive coil-type electrical products such as transformers and instrument transformers; to assess the insulation strength and withstand voltage level of the coils.
Split-type Triple Frequency Power Generator Operating Environment
1. Ambient temperature: -25℃ - 55℃
2. Altitude: not exceeding 4000 meters
3. Used for AC induced voltage withstand tests of voltage transformers, motors, and transformers, to assess the main and auxiliary insulation strength, and can also be used as a short-time 150Hz power supply.
Technical Parameters
1. Working power: Three-phase AC 380V ±10% 50Hz
2. Rated capacity: 3KVA-30KVA (optional)
3. Input voltage: 380V 50Hz sine wave
4. Output voltage: 250V-1000V 150Hz waveform distortion ≤5%
5. Output capacity: 3kVA, 5kVA, 10kVA, 20kVA, 50kVA
6. No-load operation time ≤5 minutes
7. Load operation time: 40～60s
This product is designed according to the People's Republic of China electric power industry standard DL/T848.4—2004 and the "Regulations for Preventive Tests of Electrical Equipment" issued by the former Ministry of Water Resources and Electric Power in January 1985, to meet the requirements of the power system for the frequency-doubling induced voltage withstand test equipment for high-voltage voltage transformers. It is widely used for AC withstand voltage tests of series-excited voltage transformers at 35～220kV levels in the power system, to assess the main and auxiliary insulation strength of the transformers, and can also be used for induction tests on windings of motors and small transformers; it can also be used as a short-time 150Hz power supply.
Note: The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.
