JDZ Series Single-phase epoxy resin cast voltage transformer

2025-08-10 12:39:29

I. Product Definition and Model Analysis

The JDZ series is a single-phase epoxy resin cast voltage transformer, and its naming rule follows the national standard:

-J: Voltage transformer

-D: Single-phase structure

-Z: Cast insulation

- Last digit: Rated voltage level (for example, JDZ-10 indicates 10kV level).

Its core function is to proportionally convert high voltage (such as 10kV) into standard low voltage (100V) for use by metering instruments and relay protection devices, achieving safety isolation and signal standardization.

Ii. Technical Features and Advantages

1. Structural design

- Fully enclosed casting process: The primary/secondary windings and the core are vacuum cast with epoxy resin, featuring moisture-proof, anti-pollution and maintenance-free properties, and suitable for Class II pollution environments.

- Compact size: Light in weight (about 15kg for JDZ-10), supports installation in any direction, and is suitable for the narrow space of high-voltage switch cabinets.

2. Key performance parameters

- Overload capacity: Can withstand 120% of the rated voltage for a long time and 1.9 times the overvoltage for a short time (such as in ground fault scenarios).

Partial discharge: ≤20pC (stricter than the GB 1207 standard).

Iii. Core Application Scenarios

Electric energy metering

A single unit is used for single-phase circuits, and two units are connected in V/V to measure three-phase voltage, with an accuracy of 0.2 grade to ensure the accuracy of electricity bill settlement.

2. Relay protection

The JDZX type with a residual winding (open delta connection) generates a zero-sequence voltage (3U?) to trigger ground fault protection.

3. Industry and New Energy

- High-voltage motor monitoring for steel mills/ports (JDZ-10), voltage sampling for photovoltaic power station busbar cabinets (JDZJ-6Q wet heat type).

Iv. Key Points for Selection and Operation and Maintenance

Four key elements for selection

- Voltage matching: Select based on system voltage (for example, choose JDZ-10 for a 10kV system).

- Accuracy requirements: Select 0.2S grade for measurement and 3P/6P grade for protection.

- Environmental adaptability: In hot and humid regions, select the suffix "Q/TH" (such as JDZ-10Q), and in high altitudes, choose the "GH" type.

- Capacity verification: The total power of the secondary load is ≤ the rated output (to avoid error exceeding the standard).

2. Core measures for operation and maintenance

- Short-circuit protection: Fuses or miniature Circuit breakers are installed on the secondary side.

- Regular inspection: Insulation resistance test (> 100MΩ) and accuracy verification once a year.

- Fault Prevention:

- Remove surface dirt (anti-creepage)

- Check for cracks or leaks in the epoxy resin (replace it in time).

V. Industry Trends and Technological Upgrades

- Intelligent integration: The traveling wave positioning type primary and secondary integration switch to be put into operation in Zhejiang in 2025 integrates a wibroadband sensing transformer, achieving an 80% increase in fault location efficiency.

- Material innovation: The high thermal conductivity epoxy resin casting process reduces temperature rise and extends service life.

- Standard iteration: GB/T 20840.1-2025 strengthens the error limit requirements (0.2 grade ratio ±0.2%).

Conclusion

The JDZ series, with its fully enclosed epoxy resin structure and multi-scenario adaptability, has become the cornerstone of voltage monitoring in power systems of 10kV and below. When selecting the model, it is necessary to closely adhere to the voltage level, precision requirements and environmental parameters. During operation and maintenance, the principle of "preventing short circuits, regular inspections and keeping clean" must be strictly followed. With the advancement of smart grid construction, the JDZ type transformer with integrated digital output (IEC 61850-9-2) will gradually become popular, empowering the high-reliability operation of the power grid.