CTK Type Zero-sequence Current Transformer

Introduce:

CTK Series zero-sequence current transformers are used inconjunction with relay protection devices or signals when thepower system generates zero-sequence grounding current, sothat the device components can operate to achieve protectionor monitoring.

When an electric shock or leakage fault occurs in the circuit.the secondary side of the transformer outputs a zero-sequencecurrent, so that the equipment on the connected secondarv linewill be protected (cut off the power supply, alarm, etc.)

Mainfeatures:

  • Detection of unbalanced current: ZCT is designed to measure the unbalanced current in a three-phase electrical system, which is the sum of the three phase currents. This allows them to detect ground faults, which can occur when a fault current flows from one or more of the phase conductors to ground.
  • High sensitivity: ZCT is highly sensitive and can detect even small amounts of ground fault current. This helps to prevent damage to equipment and reduce the risk of electric shock to personnel.
  • Accuracy: ZCT is designed to provide accurate measurements of the zero-sequence component of the current, even in the presence of high levels of noise or interference.
  • Non-intrusive installation: ZCT is typically installed around the neutral conductor of a three-phase system, which means that they can be installed without the need to break the circuit or interrupt power to the load.
  • Frequency response: ZCT is designed to operate over a wide range of frequencies, typically from 50Hz to 400Hz, which makes them suitable for use in a variety of applications.
  • Low burden: ZCT is designed to have a low burden, which means that they do not significantly affect the operation of the circuit or the accuracy of other measurement devices in the system.

Application:

  • Electric fire monitorin
  • Fire prevention and leakage protection system
  • Electromagnetic relaying protection
  • Microcomputer protection, etc.
Electrical parameters Mechanical parameters
Frequency 50~400Hz Shell ABS(flame retardant grade 94-V0)
Rated input 10mA~5A Bobbin PBT
Measuring range 10%In~130%In iron core Ni steel/nanocrystalline
Rated output 0~1v (A or) 0~0.25mA Internal structure Environmentally friendly epoxy resin casting
Ratio difference ≤±0.1% Construction plan Screw fixing
Phase difference ≤±10 Working temperature -25℃~ +75℃
Dielectric Strength 2.5KV/1mA/1min Ambient Humidity ≤85%
Insulation resistance DC500V/1000MΩ/min Wiring method Terminal type/shielded twisted wire 1.5m
Model Specifications Dimensions
Reference current ø A B C D E
CTK-45 ≤100A 45 104 81 95 5 28
CTK-65 ≤225A 65 124 101 115 5 28
CTK-80 ≤400A 80 138 116 130 5 28
CTK-100 ≤630A 100 158 136 150 5 28

Dimensions

FAQ

1. What is a CTK zero-sequence current transformer used for?

The CTK zero-sequence current transformer detects residual current associated with earth leakage or ground faults. It works with a compatible protection relay or monitoring device to support alarms or protective tripping. Typical applications include electrical fire monitoring, leakage protection and ground fault protection systems.

2. How do I choose the right CTK current transformer size?

Choose a window size that accommodates all conductors required by your protection scheme, with sufficient installation clearance. The CTK series offers 45 mm, 65 mm, 80 mm and 100 mm window diameters. Provide your cable dimensions, conductor arrangement and installation space so we can help select a suitable model.

3. Can the CTK zero-sequence current transformer work with my earth leakage relay?

Compatibility depends on the relay’s input requirements and the selected CTK configuration. Before ordering, provide the relay model, required input signal, residual current detection range and connecting cable length. These details help us confirm the appropriate sensor output and connection arrangement.

4. What residual current range can the CTK series measure?

The CTK series lists rated input options from 10 mA to 5 A, with a measuring range of 10%–130% of the selected rated input. These are configuration-dependent specifications, rather than one universal range for every model. Please specify your required detection range and alarm threshold when requesting a quotation.

5. How should a CTK zero-sequence current transformer be installed?

For a typical core-balance residual current application, all phase conductors of the monitored circuit pass through the same CT window. The neutral conductor must also pass through it when present, while the protective earth conductor remains outside. Follow the confirmed wiring diagram for your system, and have installation completed by qualified personnel with the circuit safely isolated.

Inquiry Now

    JOIN US

    Register as one of our members and provide you with the latest product and discount information.