Two protection-class current transformer, particularly useful in low-voltage power distribution systems, demonstrate their effectiveness in practical applications and achieve both reliability and safety . Take the PR and HPT series  from Wenzhou Heyi Electric Co., Ltd. as examples to explore their strengths .

What is the protection-class current transformer used for

Simply put, a protection-class current transformer acts like a “sentinel” in a circuit, monitoring current changes in real time near electrical equipment . If an anomaly—such as a short circuit or overload—is detected, it quickly transmits a signal to a protective device (such as a relay), allowing the system to quickly cut off power, preventing equipment damage, fire, or even personal injury.

The protection-grade ring CT we are talking about today is not used for ordinary measurement. It is specially designed for ” high-level protection ” – a high-precision, high-response, and high-reliability CT , dedicated to various high-demand protection systems .

 

Application scenarios: Where is it used 

Several typical application scenarios:

Industrial motor protection

When a large motor in a factory starts up, it carries a large current. If a stall or short circuit occurs and the power is not cut off in time, it can burn the motor at best, or even cause a fire or other safety accident .

At this time, the HEYI PR/HPT series CT can accurately capture abnormal currents and, in conjunction with motor protectors or relays, respond within seconds to protect the safety of equipment and personnel .

Commercial power distribution systems

Office buildings, shopping malls, and hospitals are places with numerous electrical wires and complex electricity usage scenarios . If a short circuit occurs in a circuit, it must be quickly located and disconnected.

It supports multi-circuit installation, can pass through multiple busbars, cooperate with the monitoring system to perform flow, power, and energy consumption analysis, and can also realize remote alarm, which is particularly suitable for intelligent power distribution management.

Automation Control System & Energy Monitoring

In order to save energy and reduce emissions , many companies have installed power monitoring systems and energy consumption management systems.

This protection-grade CT not only provides protection, but also provides stable and accurate current signals for power metering, load analysis, and automatic control. It is suitable for a variety of usage scenarios and has a high cost-effectiveness !

Highly compatible with relay protection devices

This is the most important scenario for protection-level CT

For example, the Heyi HPT series protection-class current transformer clearly states : “Specially designed for relay protection circuits.” It can detect short-circuit fault signals and transmit data at the moment the fault occurs , ensuring that the circuit breaker cuts off power in time to avoid electrical accidents .

Why is it said to be so protective? Three key features!

Highlight 1: High protection level, fast and accurate response !

Heyi PR series protection-class current transformer are marked with protection-grade accuracy such as PR-10P5, PR-10P10, and PR5P10.

What does it mean? For example: 10P10 means that at 10 times the rated current, the error does not exceed 10% – this is crucial in the event of a short circuit!

The short-circuit current may be dozens of times higher than the normal current, and ordinary CT will lose its effectiveness , but protection-grade CT can still accurately output signals, allowing the protection device to “see clearly” what is happening.

Conclusion: Only when the current data is correct at the critical moment can it be truly reliable!

Highlight 2: Thoughtful structural design, easy installation and maintenance

Ring opening design: No need to turn off the power and remove the wires, just “click” it and put it on the busbar, saving time and effort.

Small size and light weight: The HPT series  protection-class current transformer places special emphasis on “miniaturization” and is suitable for distribution cabinets with limited space.

A variety of apertures are available (such as HPT-40 to HPT-135), suitable for busbars of different thicknesses, and highly compatible.

The shell is made of flame retardant and high temperature resistant material (not afraid of 140℃), which meets safety standards and is not afraid of high temperature aging.

Highlight 3: Strong adaptability and can withstand various “harsh environments”

Working temperature: -30℃ ~ 70℃, can withstand low temperatures in winter and high temperatures in summer .

Strong voltage resistance: 3000V power frequency voltage resistance for 1 minute, excellent insulation performance, not afraid of voltage fluctuations.

The protection scenario is clear: it is suitable for indoor environments without direct rain or snow, severe pollution, and vibration – which just covers most distribution rooms and control cabinets.

Parameter highlights of HEYI protection-grade current transformers

Parameter comparison of two protection level current transformers :

PR Series | 60/5A to 5000/5A | 5A | 10P5, 10P10, 5P10 | Up to 5VA |

HPT Series | 200A to 6300A | 5A/1A/0.1A | 5P/10P | Up to 30VA

The HPT series supports 1A output, which is more suitable for long-distance transmission and reduces signal attenuation.

Larger capacity (up to 30VA), capable of carrying more loads, suitable for complex protection systems.

The primary current covers a wide range and can be used from small equipment to large transformers.

This means: one set of products covers multiple usage scenarios, saving you worry and cost!

Why is it recommended

If you are an electrical engineer, project manager, or are selecting power distribution components, this ring CT deserves your attention for three reasons:

1.The protection is really strong: it is not “almost okay”, but it can respond accurately at the moment of failure to maintain the bottom line of safety.

2.Flexible application: capable of measurement, monitoring, protection and energy saving, one device can be used for multiple purposes.

3.From a reliable manufacturer, HEYI Electric specializes in low-voltage transformers, and its products are certified and standardized .

Summarize

This protection-grade toroidal current transformer is not only a “sensor”, but also a “safety guard” for the circuit.

With its high-precision protection level, flexible installation method and stable performance, it silently guards the safety of every kilowatt-hour of electricity in the fields of industry, commerce, automation, etc.

Whether it is matching relays, monitoring energy consumption, or building intelligent power distribution systems, it is the reliable, trustworthy, and long-lasting “behind-the-scenes hero.”

If you are looking for a cost-effective, highly reliable, and highly adaptable protection-grade CT, you might want to take a look at the PR and HPT series, which may be the “optimal solution” you are looking for.

Compay：HEYI Electrical Co., Ltd.

Brand: HEYI/ASCT

Contact: Bethy

E-mail: heyi@heyiele.com             

Tel: 86-13968747975

--- END ---