What is Relay Protection? How does protecting current in the electrical system work?

Voltage protection relay is an automatic device designed to help the system operate stably and safely. But what are the characteristics of a voltage protection relay? What is its practical use? Let's find out with EMIN in the article below!

What is a voltage protection relay?

Have you ever worried that your home's electrical equipment will be damaged by electrical incidents such as overload, unstable voltage or even lightning strike? These problems are not only annoying but also pose the risk of serious damage to the entire electrical system.  

Voltage protection relay is the solution for you. This device is designed to protect the home electrical network comprehensively, from controlling high, low voltage, overload to detecting errors such as phase loss, phase imbalance or wrong phase sequence. In particular, the relay also helps prevent damage to the motor and connected devices when the system encounters unusual problems..  

What are the benefits of voltage protection relays?

- Overvoltage and undervoltage protection: When the input voltage exceeds or is lower than the safety threshold you have set (usually 220V), the relay will automatically disconnect power, avoiding damage to the devices. electrical equipment.  

- Overcurrent protection: If the current exceeds the limit, this device will cut off the power immediately, preventing the risk of electric shock, fire and equipment damage.  

- Display parameters clearly: With two modern LED screens, you can easily monitor and control the voltage and current in your family. 

- Automatic recovery: When the parameters return to a safe level, the relay will automatically turn the power back on, helping electrical devices operate normally without manual intervention. 

- Effective lightning protection: In case of lightning causing a sudden increase in voltage and current, the relay will quickly disconnect, protecting the electrical system from damage.  

-Flexible parameter customization: Easily set parameters to suit your family's needs. 

What criteria should be met before purchasing a voltage protection relay?

When choosing to buy a voltage protection relay, understanding the necessary criteria is extremely important to ensure optimal protection effectiveness. So what are the factors you need to keep in mind?  

- Accurate selection: The relay needs to detect and properly handle the faulty element without affecting other parts.  

- Absolute selectivity: Precise protection within a defined range, does not interfere with neighboring elements.  

- Relative selectivity: In addition to protecting the main object, the device can also play a backup role when other elements fail.  

- Fast action: Processing speed is the decisive factor when facing incidents such as short circuits or low voltage. The faster the reaction time, the greater the potential for damage mitigation.  

- Main protection usually operates for about 0.2 – 1.5 seconds.  

- Backup protection lasts from 1.5 - 2 seconds to ensure coordination throughout the system.  

- High sensitivity: The sensitivity coefficient helps the relay accurately sense errors in the system:  

- Main protection requires a sensitivity coefficient of 1.5 – 2.  

- Backup protection requires sensitivity of 1.2 - 1.5.  

Whether the electrical system is large or small, home or business, installing voltage protection relays is essential. Depending on the intended use, you can choose the appropriate type of relay such as: single-phase voltage protection relay, power monitoring relay, phase loss or reverse phase protection relay.