1. Introduction

Electrical equipment is exposed to various physical phenomena in high-voltage and high-energy environments, and the representative electrical abnormalities are arc and surge. Quantitative comparison and analysis of the causes, characteristics, damage types, and interrelationships of the two phenomena.

2. Analysis of the cause of occurrence

Arc

• Occurs when the insulating medium (air, etc.) between two electrodes is ionized by high voltage, forming a plasma passage .

• Sudden changes in current: switching, short circuits, inductor operation, etc.

• When the insulation exceeds its withstand voltage limit and insulation breakdown occurs

Surge

• Inflow due to natural phenomena: lightning, induced voltage

• Internal factors: switching operations of circuit breakers, relays, motors, transformers, etc.

• Others: sudden voltage changes such as electrostatic discharge, power line short circuit, etc.

3. Arc vs Surge Comparison

4. Interconnection between Arc and Surge

Arc → Surge

• When the current flowing in the circuit is suddenly cut off due to the opening or closing of a switch or circuit breaker , a counter electromotive force is generated by the inductance (coil, etc.)

• At this moment, an arc occurs and the current is suddenly cut off , forming a high surge voltage (current cutting phenomenon).

Surge → Arc

• When the transient voltage generated by lightning or switching exceeds the insulation strength of the insulator, insulation breakdown occurs, inducing an arc discharge.

• These arcs can cause additional secondary damage (equipment damage, fire).

5. Conclusion

• Arcs and surges have different mechanisms, but they can cause each other in electrical installations.

• Both phenomena are characterized by high energy and short response times, which can lead to equipment failures and safety accidents.

Protection measures

• Design of arc suppression devices such as arc killers and vacuum circuit breakers

• Selecting the appropriate rating and location of SPD (surge protection device)

• Design application that considers insulation performance enhancement and inductance within the circuit

Arcs and surges that can occur in electrical equipment are both transient states in which rapid electrical phenomena occur in a short period of time. However, these two phenomena

Significant differences in the principle of occurrence, duration , and rate of increase of current and voltage .

Time characteristics of surge

concept

• Transient voltage or current that occurs momentarily in an electrical circuit or facility

• The occurrence time is typically in the order of several ns (nanoseconds) to μs (microseconds).

Surge waveform velocity example

Surges usually cause rapid voltage and current changes in a short period of time, which can cause momentary damage or malfunction to equipment.

3. Time characteristics of Arc

concept

• When the insulating medium (air, etc.) between two conductors (electrodes) is ionized , a plasma path is formed → current flows.

• A phenomenon that occurs quickly but has the potential to last

Arc velocity example

Arcs are accompanied by light, heat, and sound, and can cause fire and electric shock hazards because continuous current flow can be maintained for long periods of time.

4. Summary of comparison of time characteristics

5. Conclusion

• Surge is a momentary transient phenomenon (μs~ns) that causes malfunction of precision equipment or insulation breakdown.

• Arcing is a continuous current flow (several milliseconds to seconds) that occurs over a long period of time due to insulation breakdown, posing a great risk to equipment and human life.

• Both phenomena require fast-reacting protective devices (SPDs, arc killers, etc.) and thorough circuit design.

reference

• Arc and surge protection design must be based on IEC standards and domestic electrical installation technical standards , and it is important to have an appropriate diagnostic and monitoring system in place.