Technical Overview and Design Considerations of DDG Series High-Current Generators for Power System Testing

The DDG Series High-Current Generator is a specialized electrical testing apparatus designed for power utilities and industrial facilities to perform critical current load tests, thermal rise evaluations, and calibration of protective devices. Engineered to deliver precise and stable high-current outputs, this equipment supports applications such as primary busbar protection, current transformer (CT) ratio verification, and relay/breaker setting validations. With modular designs ranging from compact integrated units to split configurations for high-capacity requirements, the DDG series addresses diverse testing needs while prioritizing operational safety and reliability.

Key Design Features

1.Dual-Range Current Monitoring
Equipped with two independent ammeters, the system enables simultaneous monitoring of both primary and secondary current values. This dual-range capability ensures accurate measurement across varying load conditions, from low-current precision tests to high-current stress evaluations.

2.Autotransformer-Based Current Control
A finely adjustable autotransformer provides smooth, stepless current regulation (0–rated current). This design eliminates abrupt load transitions, reducing electromagnetic stress on test objects and enhancing measurement repeatability.

3.Intuitive Human-Machine Interface (HMI)
Simplified operator interaction is achieved through status indicator lights and tactile push-button controls. The interface supports rapid configuration changes while maintaining compliance with IEC safety standards for high-current environments.

4.Modular Structural Design

Integrated Units (≤3000A): Compact monoblock architecture minimizes footprint for field deployments.

Split Systems (>3000A): Segregated transformer and control modules reduce weight per component (e.g., 180kg total for 8000A model) while improving thermal management and transport flexibility. 

Notes:

1.Duty Cycle: Designed for 5-minute short-term operation. For intermittent use, limit ON-time to ≤2.5 minutes with ≥10-minute cooling intervals.

2.Output Voltage: Fixed 6V secondary voltage optimizes compatibility with standard test object impedances (e.g., switchgear, CTs).

3.High-Efficiency Design: 20000A model achieves 200% current scaling vs. 10000A variant at identical 60kVA capacity through advanced magnetic circuit optimization.

Typical Applications

1.Protective Relay Testing
Validate instantaneous/timed tripping characteristics of overcurrent relays (e.g., IDMT curves) up to 20kA fault simulations.

2.CT Ratio/Polarity Verification
Inject secondary currents up to 10000A for accuracy class assessments per IEEE C57.13.

3.Circuit Breaker Thermal Withstand Tests
Simulate continuous rated currents (e.g., 4000A for 2.5 minutes) to evaluate contact resistance and insulation degradation.

4.Busbar Joint Resistance Measurement
Apply 500–2000A currents to detect micro-ohm level resistance variations in substation connections.

Operational Guidelines

1.Pre-Test Preparation: Verify input voltage compatibility (200V/220V/380V variants) and ensure adequate cooling for split configurations.

2.Safety Protocols: Use IR-certified gloves and face shields during high-current (>3000A) tests due to intense magnetic fields.

3.Maintenance: Perform annual insulation resistance tests (≥100MΩ at 2500V DC) and autotransformer contact inspections.

The DDG Series High-Current Generator combines precision engineering with rugged field adaptability, making it indispensable for modern power system commissioning and maintenance. Its scalable architecture—from 500A integrated units to 20kA split systems—ensures cost-effective solutions for utilities, OEMs, and industrial testing teams. Future iterations are expected to integrate IoT-enabled load profiling and adaptive thermal derating algorithms for enhanced operational intelligence.

GDZX is a manufacturer of power testing equipment, offering a wide range of product categories with comprehensive models and providing professional technical support. Contact: +86-17396104357.Website: https://www.highvoltage-testequipment.com/