Definitions and functions of commonly used overvoltage protection

Definition and function of overvoltage protection: Overvoltage protection (OVP) is a protection method that disconnects the power supply or reduces the voltage of the controlled equipment when the voltage exceeds a predetermined maximum value. Its purpose is to prevent the power supply from inputting excessively high voltages to sensitive devices, thereby protecting the equipment from damage due to excessive voltage.¹²

A common method for overvoltage protection is using Zener diodes: Zener diodes can operate normally under overvoltage conditions, controlling the voltage through current to prevent the voltage from exceeding a preset value. For example, a 5.1V Zener diode will operate when the voltage exceeds 5.1V, limiting the voltage below 5.1V.

Thyristor Crowbar: This is a circuit that quickly activates upon detecting an overvoltage condition, short-circuiting the output to protect the equipment. SCR circuits are sometimes called "crowbar" circuits because they short-circuit the output instantaneously during an overvoltage event.² Voltage Clamping: Voltage clamping circuits limit the voltage to a safe range to prevent overvoltage.³ Overvoltage Protection Relay: Relays disconnect the circuit during an overvoltage event to protect the equipment.⁴

The principle and application scenarios of overvoltage protection: Overvoltage protection mechanisms are commonly used in power supply design to prevent excessively high output voltage. The overvoltage protection function in a power supply can respond immediately upon detecting an overvoltage, shutting down the output or providing short-circuit protection. For example, linear power supplies include overvoltage protection circuitry in their design to ensure a rapid response in the event of an overvoltage, protecting the equipment from damage.² In addition, surge arresters are also a common method of overvoltage protection, used to prevent overvoltages caused by external factors such as lightning.⁴

Overvoltage protection is an important safety mechanism used to ensure that various electronic devices, electrical systems, and industrial equipment are effectively protected when voltage levels rise abnormally. By monitoring voltage levels in circuits and taking appropriate measures, overvoltage protection systems help prevent accidents such as equipment damage, data loss, or fires.

1. What is overvoltage protection?

Overvoltage protection is a technical measure used to monitor voltage levels in a circuit and protect equipment from damage when abnormally high voltages are detected. Overvoltages can be caused by power grid failures, lightning strikes, operational errors, or other reasons, posing a potential risk to equipment and systems.

2. Principle of Overvoltage Protection

Overvoltage protection systems typically use voltage sensors to monitor voltage levels in a circuit. These sensors can be resistive, capacitive, or amplifier-type, and they ensure the circuit operates within a safe range by detecting voltage changes in real time.

The control unit is the core component of the overvoltage protection system. It is responsible for receiving data from the voltage sensor and making judgments based on preset voltage thresholds. Once a voltage exceeding the set threshold is detected, the control unit will activate the corresponding protection measures.

3. Types of overvoltage protection

1. Warning-type overvoltage protection: This type of overvoltage protection system issues a warning signal before the voltage reaches a dangerous level, reminding operators to take timely measures to avoid equipment damage. This type of protection typically requires manual intervention to resolve the issue.

2. Automatic Overvoltage Protection: Automatic overvoltage protection systems immediately cut off power when an excessively high voltage is detected to prevent equipment damage. This type of protection is suitable for applications requiring rapid response and protection of equipment from voltage surges.

4. Overvoltage protection operating mode

1. Real-time monitoring: The overvoltage protection system continuously monitors the voltage in the circuit in real time in order to detect and respond to abnormal voltage situations in a timely manner.

2. Trigger protection measures: Once the voltage exceeds the set threshold, the overvoltage protection system will trigger corresponding protection measures, such as cutting off the power supply, reducing the voltage, or adjusting the circuit connection.

5. Advantages and limitations of overvoltage protection

advantage:

Provides additional safety protection to prevent equipment from being damaged by excessive voltage.

It helps extend equipment life and reduce maintenance costs.

Improve the stability and reliability of equipment operation.

limitation:

There is a risk of false alarms, which could cause the equipment to stop working frequently.

Some overvoltage protection systems require manual reset, which affects the continuous operation of the equipment.

6. Application areas of overvoltage protection

1. Electronic equipment: Overvoltage protection systems are widely used in various electronic equipment, such as computers, televisions, and audio systems, to ensure that the equipment can operate normally and be protected from damage under abnormal voltage conditions.

2. Power System: In power systems, overvoltage protection technology is crucial for maintaining system stability and reliability. By monitoring voltage in transmission lines and substations, overvoltage protection systems can respond promptly to emergencies such as grid faults or lightning strikes, reducing the impact on the entire power system.

3. Industrial Automation: Equipment and control systems in industrial production processes have very high requirements for voltage stability. Overvoltage protection systems play a crucial role in industrial automation, protecting various critical equipment from the dangers of excessive voltage and ensuring the safety and continuity of production operations.

4. Building sector: Overvoltage protection devices are also needed in the electrical systems inside buildings to prevent damage to lighting fixtures and electrical equipment, or even fires, caused by high voltage.

Overvoltage protection, as a key safety technology, is widely used in various fields, providing important protection for our lives and work. By promptly identifying abnormal voltages in circuits and taking effective protective measures, overvoltage protection systems help us avoid many voltage-related accidents and losses, protecting the safety of equipment and personnel.

A device that can intelligently and automatically cut off the power supply quickly and automatically when the mains voltage suddenly exceeds, falls below, or becomes undervoltage is called an overvoltage, over-voltage, or undervoltage protector. When using any electrical appliance, it is crucial to avoid excessively high or low mains voltage. Both industrial equipment and household appliances have rated voltages, typically ranging from 170V to 240V. Exceeding this voltage will exceed the insulation strength and withstand voltage of the appliance, causing it to overheat, break down, and burn out, or even catch fire. By now, you should understand what overvoltage protection is. Safe, scientific, and intelligent use of electricity can ensure that appliances will not burn out, be destroyed, or catch fire due to abnormal mains voltage or input power, thus effectively protecting life and property.

Overvoltage protection, also known as voltage protection, refers to a protection method that disconnects the power supply or reduces the voltage of the controlled equipment when the voltage of the protected line exceeds a predetermined maximum value. Common overvoltage protection components or devices include surge arresters, rheostats, etc. In the field of communication power supplies, to prevent the huge damage caused by instantaneous high voltage from lightning, varistor protection, overvoltage protection, and lightning protection are usually used. Depending on the needs of the times, there are many types of overvoltage protectors; some are installed inside the equipment, and some are installed on the power supply side. With the protection of overvoltage protectors, we are safer when using electrical equipment. Overvoltage protection refers to a protection method that disconnects the power supply or reduces the voltage of the controlled equipment when the voltage of the protected line exceeds a predetermined maximum value. What is the service life of an overvoltage protector? Overvoltage protectors are a new type of overvoltage protector used to limit atmospheric overvoltages and operational overvoltages caused by various vacuum switches. They can protect against phase-to-phase and phase-to-ground overvoltages. One protector can replace several surge arresters, and its function is unmatched by ordinary surge arresters.