Dielectric Loss Tester
The dielectric loss tester is a high-precision testing instrument used in power plants, substations, and other field or laboratory settings to measure the dielectric loss tangent and capacitance of various high-voltage power equipment.The instrument features an integrated structure, incorporating a dielectric loss test bridge, a variable-frequency voltage-regulating power supply, a step-up transformer, and an SF6 high-stability standard capacitor. The test high-voltage source is generated by the internal inverter and stepped up by the transformer for testing the specimen. The frequency can be varied to 45Hz or 55Hz, and 55Hz or 65Hz, using digital notch technology to avoid interference from the power-frequency electric field, fundamentally solving the problem of accurate measurement under strong electric field interference. It is also suitable for testing with generator power supply after a complete power outage. When equipped with an insulating oil cup, the instrument can test the dielectric loss of insulating oil.
Main Features:
1. Large LCD Chinese display
The instrument is equipped with a large screen (105mm×65mm) Chinese menu interface. The screen is divided into left and right parts: the left side is the function menu area, and the right side provides relevant status information prompts. Each step is very clear, and operators can use it without professional training. With one operation, the microcomputer automatically completes the entire measurement process, making it an ideal dielectric loss measurement device.
2. Massive data storage
The instrument is equipped with a calendar chip and large-capacity memory, which can save test results in chronological order, allowing for viewing of historical records at any time and print output;
3. Scientific and advanced data management
Instrument data can be exported via USB drive, and can be viewed and managed on any PC using our company's dedicated software, and work reports can be generated.
4. Multiple test modes
The instrument can test using various modes such as internal high voltage, external high voltage, internal standard, external standard, positive connection method, reverse connection method, and self-excitation method; under external standard and external high voltage conditions, it can perform high-voltage (greater than 10kV) dielectric loss tests.
5. One-step CVT testing
The instrument can also test the dielectric loss and capacitance of C1 and C2 of fully sealed CVTs (capacitor voltage transformers), achieving simultaneous testing of C1 and C2. The instrument can also test the CVT ratio and voltage phase angle difference.
6. High-speed signal sampling
The internal inverter and sampling circuit of the instrument are fully digitally controlled, and the output voltage is continuously adjustable.
7. Multiple protections for safety and reliability
The instrument is equipped with multiple protection measures such as input voltage fluctuation, output short circuit, overvoltage, overcurrent, and temperature, ensuring the safety and reliability of the instrument. The instrument also has a grounding detection function to ensure that ungrounded equipment is not allowed to boost voltage.
Working Principle:
Under the action of AC voltage, the dielectric consumes part of the electrical energy, which is converted into heat energy and causes loss. This energy loss is called dielectric loss. When an AC voltage is applied to the dielectric, there is a phase angle difference Ψ between the voltage and current in the dielectric. The complementary angle δ of Ψ is called the dielectric loss angle, and the tangent of δ, tgδ, is called the dielectric loss tangent. The tgδ value is a parameter used to measure dielectric loss. The instrument's measurement circuit includes a standard circuit (Cn) and a test circuit (Cx). The standard circuit consists of a built-in high-stability standard capacitor and the measurement circuit, while the test circuit consists of the test object and the measurement circuit. The measurement circuit is composed of a sampling resistor, a preamplifier, and an A/D converter. Through the measurement circuit, the amplitude and phase of the standard circuit current and the test circuit current are measured respectively, and then using a microcontroller with digital real-time acquisition methods and vector operations, the capacitance value and dielectric loss tangent of the test object can be obtained.
The instrument has built-in anti-interference measures to ensure accurate measurement under external electric field interference.
