Overview

Currently, in 6–66 kV medium-voltage power supply systems, all arc-suppression devices available on the market for protecting against and handling single-phase-to-ground faults suffer from various shortcomings and drawbacks. These devices often exhibit limitations such as single-functionality in fault protection and handling, particularly with regard to the accuracy of precise fault line selection. As a result, they fall short in ensuring stable and continuous power supply following a fault occurrence and face significant challenges in addressing space constraints, especially in particularly narrow or confined installation environments.

Based on the existing problems with various arc-suppression and protection devices currently available, and drawing on our company’s many years of expertise in this field as well as our meticulous design efforts, we have developed and completed the “DT-DZX20 Series Single-Phase Ground Fault Comprehensive Processing Device.”

Function Description

Capacitive current automatic real-time tracking and measurement function;

Arc-suppression coil automatic tracking compensation function; the arc-suppression coil employs a magnetically controlled, continuously adjustable compensation method.

Equipped with the AS1700 precision line-selection system, this system offers highly accurate line selection and effectively addresses the challenge of precise line identification in multi-level power grid systems—specifically those featuring secondary or tertiary switchgear substations.

The ground fault line selection function can monitor up to 72 outgoing circuits (the standard model monitors 42 circuits).

Optional ground fault circuit tripping function and delayed tripping function are available;

The ground fault status analysis function can identify transient ground faults lasting less than 10 seconds as well as sustained ground faults exceeding 10 seconds.

The “fault-phase identification” function can quickly identify the phase experiencing a ground fault.

The fault is grounded via a metallic connection, and a metallic grounding protection buffer system for the faulted phase has also been configured.

After a single-phase-to-ground fault occurs in the system, timely arc-suppression coil compensation is performed to bring the fault current in the system down to the specified value. Once the device detects a ground fault lasting longer than 10 seconds, it will perform metallic grounding on the faulted phase and simultaneously disconnect the arc-suppression coil.

The configured arc-suppression coils are divided into arc-suppression coils with a 2-hour standard long-term compensation output and arc-suppression coils with a 20-second short-term compensation.

Optional comprehensive fault detection and waveform recording functions are available;

The on-site installation structure comes in various forms and options, including box-type enclosures and standard high-voltage switchgear configurations. The equipment can be installed independently indoors or outdoors, and can be directly integrated into existing switchgear cabinets on-site. The primary and control sections can be designed and installed as an integrated unit, or the secondary components can be arranged in modular panels, allowing the primary and secondary sections to be installed separately. The installation methods are flexible, diverse, convenient, simple, and aesthetically pleasing.

The complete set of equipment can be directly connected to the system power supply without requiring a dedicated switchgear for additional power input.

This complete set of equipment can be supplied either as a multifunctional integrated unit or broken down into separate components: an independent arc-suppression compensation device, an independent precision line-selection device, and a comprehensive ground-fault handling unit that supports an expandable neutral-point small-resistance grounding mode.