Fully Automatic Anti-interference Dielectric Loss Tester

The MOEORW-W801CD3 is a fully automatic anti-interference dielectric loss tester (also referred to as a tan delta tester or insulation loss tester) specifically designed for substations, power plants, and high-voltage equipment manufacturing sites. Utilizing variable-frequency power supply technology and digital signal processing algorithms, this instrument accurately measures capacitance (Cx) and dielectric loss factor (tgδ) even in strong electromagnetic interference environments. This anti-interference tan delta tester also integrates insulation resistance testing, automatic LCR measurement, and CVT ratio verification, truly achieving multi-functionality in one unit. It serves as a core tool for preventive insulation testing of high-voltage electrical equipment.

This product is widely applicable to the following typical scenarios and is an indispensable variable-frequency dielectric loss tester for the power maintenance and manufacturing industry:

Whether in high-interference outdoor substation environments or precision comparison tests in laboratories, this fully automatic anti-interference dielectric loss tester delivers stable and reliable measurement results.

Variable-Frequency Anti-Interference Technology – Accurate Data Even in Complex Environments

The greatest challenge in field testing comes from strong 50Hz power-frequency electric fields and their harmonics. This dielectric loss tester employs the variable-frequency method, outputting single frequencies within 45Hz~65Hz and multiple dual-frequency pure sine wave combinations (e.g., 47.5Hz/52.5Hz, 55Hz/65Hz), automatically filtering out on-site interference.

Internally, the instrument performs complex number operations on signals via Fourier transform, precisely extracting fundamental components from noise. According to factory calibration data, even under extreme conditions where interference current reaches twice the test object current (200% interference), the following accuracy is guaranteed:

• tgδ accuracy: ±(reading × 1.0% + 0.040%)
• Cx accuracy: ±(reading × 1.0% + 1.00pF)

This specification already exceeds the accuracy requirements for Class A instruments stipulated in DL/T 962-2005 "General Technical Specifications for High-Voltage Dielectric Loss Testers." This means that even in high-interference areas such as 500kV switchyards, you can obtain laboratory-grade reliable data without power outage or expensive shielding structures.

Smart CVT Testing – Complete All Measurements with One Connection

Traditional dielectric loss testing of CVTs (capacitor voltage transformers) requires multiple connections and disconnections of high-voltage leads, involving cumbersome procedures and risks of working at height. This tan delta tester is equipped with a built-in self-excitation power supply (AC 0~50V/15A, single-frequency and dual-frequency adjustable), offering three dedicated CVT operating modes:

• Separate Testing: Independently measures capacitance and tgδ of C1 or C2
• Simultaneous Testing: With one connection, synchronously completes full parameter measurement of both C1 and C2, reducing test duration from the traditional 1 hour to within 5 minutes
• CVT Ratio Testing: Supports ratio verification for CVT devices from 35kV to 500kV (ratio range 10~10000, accuracy 1%)

This functionality directly addresses the mandatory requirement in "State Grid Corporation's 18 Major Anti-Accident Measures for Power Systems" for regular dielectric loss and capacitance testing of CVT equipment, improving on-site operational efficiency by over 60%.

High-Voltage Shielding in Reverse Connection – Measure C11 Without Disconnecting Leads

For situations where CVT busbars cannot be de-energized or lead disconnection is difficult, this anti-interference dielectric loss tester features both low-voltage shielding in reverse connection and high-voltage shielding in reverse connection. With the busbar grounded, it can perform non-disconnection 10kV reverse-connection dielectric loss measurement on the upper C11 capacitor of the CVT.

This function eliminates the need for repeated aerial lift operations, making it particularly suitable for annual preventive testing of CVTs at 220kV and above, effectively reducing safety risks and shortening outage windows.

Four-Channel Simultaneous Measurement – Multiplied Efficiency in Batch Testing

This fully automatic anti-interference dielectric loss tester is equipped with four independent measurement channels (Cx1~Cx4), allowing simultaneous connection of four test objects (e.g., four sets of instrument transformers or four-phase bushings). With a single click, the instrument synchronously acquires four sets of tgδ and capacitance data.

At 10kV high-voltage output, total capacitance across four channels is <60nF; at 5kV, <150nF; at 1kV, <300nF. This design is particularly suitable for batch factory inspections and production-line aging tests, delivering four times the data output within the same single test cycle.

Integrated Insulation Resistance and LCR – Eliminate the Need for Multiple Devices

Beyond dielectric loss measurement, this unit also functions as an insulation resistance tester and an LCR bridge:

• Insulation Resistance Testing: DC high voltage 0.5~10kV adjustable, accuracy ±(reading×2%+10V), resistance accuracy ±(reading×1%+0.1MΩ). Supports automatic calculation of Polarization Index (PI) – the ratio of insulation resistance at 10 minutes to that at 1 minute, and Dielectric Absorption Ratio (DAR) – the ratio of insulation resistance at 1 minute to that at 15 seconds. These two parameters are critical criteria for assessing moisture ingress and insulation aging in large power transformers, fully compliant with DL/T 596-2021 "Preventive Test Procedures for Electric Power Equipment."
• Automatic LCR Measurement: Measures inductance L (>20H), resistance R (>10kΩ), with angle resolution of 0.01° and angle accuracy of 1%. Ideal for rapid screening of voltage-withstand rated inductors, capacitors, and resistors.

One instrument covering dielectric loss, insulation resistance, and LCR functions significantly reduces on-site equipment count, lowering calibration and maintenance costs.

Built-In Wiring Diagram Guidance – Zero-Threshold Operation

The instrument is equipped with a large LCD screen, and under each function interface, the corresponding wiring schematic diagram is built in. After the operator selects modes such as "Standard Test," "CVT Test," or "Insulation Test," the screen immediately displays the standard wiring topology, clearly illustrating methods such as positive connection, reverse connection, and external high-voltage connection. Even novices unfamiliar with the principles can complete preparations in three steps – "connect wires, select parameters, press start" – following the on-screen diagrams, greatly reducing training costs and preventing equipment damage or invalid tests caused by incorrect wiring.

Multiple Hardware and Software Protections – Safety Throughout the Entire Process

Safety in high-voltage testing is the foremost priority. This variable-frequency dielectric loss tester incorporates a complete protection chain at both hardware and software levels:

• Overcurrent Protection: In the event of short circuit or breakdown of the test object, the high-voltage output is cut off within microseconds, protecting both the instrument itself from damage and the test object from impact
• Reverse-Connection Digital Isolation Communication: Employs precision MPPM digital modems with isolation voltage up to 20kV, ensuring physical separation between the operator and the high-voltage circuit
• Grounding Detection: The instrument automatically verifies whether the ground terminal is reliably connected; voltage boost is prohibited when not grounded
• Smooth Ramp-Up/Ramp-Down Technology: The variable-frequency power supply uses a PID algorithm to smoothly raise and lower the high-voltage output at a rate of 0.5kV per second, avoiding step-voltage impact on the test object's insulation
• Discharge Reminder: Upon test completion, the instrument automatically discharges residual charge from the test object and prompts "wait one minute before disconnecting," in compliance with DL/T 848.2-2004 safety operation specifications

Each MOEORW-W801CD3 packaging box contains all of the following accessories, ready for use upon unboxing:
High-voltage test cable (HV) ×1 unit
Low-voltage test cables (Cx1~Cx4) ×4 units
External standard capacitor test lead (CN) ×1 unit
CVT self-excitation power output lead ×1 unit
Dedicated grounding wire (with grounding clip) ×1 unit
3-core power cord (AC 220V) ×1 unit
Spare fuses (same specification) ×2 units
Factory calibration certificate ×1 copy
Product user manual (including safety regulations) ×1 copy
Certificate of conformity ×1 copy