What is Surge?

Ⅰ. What is surge?

Surge, as the name suggests, is an overvoltage that occurs suddenly and surpasses the typical operating voltage. A surge is a brief wave of current, voltage, or power in a circuit, in general. Surges or transients are sub-periodic overvoltages lasting less than half the period of the regular voltage waveform in power systems, and this is probably the most common background we connect with surges. Surges can be positive or negative, adding or subtracting from regular voltage waveforms, and oscillating and decaying over time. Heavy machinery, short circuits, power switching, and powerful engines are all potential sources of surges. Surge-blocking devices in products can successfully absorb huge bursts of electricity, preventing damage to linked equipment.

A surge, also known as a transient, is a sudden overvoltage spike or disturbance in the power waveform that can harm, degrade, or destroy electronic equipment in any house, business building, industrial, or manufacturing plant. Transients can reach tens of thousands of volts in magnitude. The time it takes for a surge to occur is commonly measured in microseconds.

Every piece of electrical equipment is made to work at a specific nominal voltage, such as 110 volts, 220 volts, or 24 volts. Surges.  on the other hand, can be severely harmful to practically all equipment. Most equipment is built to manage modest fluctuations in its typical nominal operating voltage.

Ⅱ. Surge/Transient Source

Switching electrical equipment is a common source of surges in buildings. This could be anything from a basic thermostat that controls a heating element to a switch-mode power supply that is used in many gadgets. Surges induced by lightning and power grid switching are examples of surges that originate outside the facility.

Transients can come from both inside and outside the institution (internal and external sources):

Surges are created 60-80% of the time within the plant.

Ⅲ.  The characteristics of surge

The surge has a very short duration, on the order of picoseconds. When a surge occurs, the voltage and current amplitudes are more than twice what they are normally. Because the input filter capacitor charges quickly, the peak current is substantially higher than the steady-state input current. The surge level that  AC  switches, bridge rectifiers, fuses, and  EMI  filter components can withstand should be limited by the power supply. The  AC input voltage should not harm the power supply or cause the fuse to blow while switching the loop repeatedly.

This phenomenon only lasts a few nanoseconds to a few milliseconds in most cases.

At the time of the surge, the voltage and current are more than twice what they should be.

Ⅳ. The performance of surge

Surge is ubiquitous in power distribution systems, which means that surges are everywhere. The main manifestations of surge in the power distribution system are:

Voltage fluctuation

The machine equipment will automatically stop or start under typical working conditions.

Electrical equipment includes air conditioners, compressors, elevators, pumps, and motors.

The computer control system frequently resets itself for no apparent reason.

Frequently, motors are changed or rewound.

Electrical equipment's lifespan is shortened as a result of failures, resets, or voltage issues.

The effects of surges on sensitive electrical and electronic equipment are of the following types:

Destroy

Voltage breakdown of semiconductor devices

Destroy the metalized surface of components

Destruction of printed circuit board traces or contacts

Destruction of triacs/thyristors...

Interference

Lockup, thyristor, or triac out of control

Partial corruption of data files

Data processing program error

Errors and failures in receiving and transmitting data

Unexplained failures...

Premature aging

Parts are aged in advance, and the life of electrical appliances is greatly shortened

The output sound quality and picture quality are degraded

Ⅴ.  The source of surge

The surge can be separated into two sorts using the power distribution system as a model: outside the system and inside the system. According to statistics, the surge outside the system is primarily caused by lightning and the impact of other systems, accounting for approximately 20% of the total; the surge inside the system is primarily caused by the impact of the power load within the system, accounting for approximately 80% of the total.

• Internal – electrical equipment switches, etc.

• External - mostly lightning strikes

Internal source:

Switching of electrical loads

The surge can be separated into two sorts using the power distribution system as a model: outside the system and inside the system. According to statistics, the surge outside the system is primarily caused by lightning and the impact of other systems, accounting for approximately 20% of the total; the surge inside the system is primarily caused by the impact of the power load within the system, accounting for approximately 80% of the total.

Sources of switching and ringing surges include:

1. Contactor, relay, and circuit breaker operation

2. Switching of capacitor banks and loads (eg power factor correction)

3. Discharge of induction equipment (motors, transformers, etc.)

4. Load start and stop

5. Fault or arcing

6. Arc (ground) fault

7. Fault clearing or interruption

8. Power system restoration (power outage)

9. Loose connections

Magnetic induction coupling

A magnetic field is formed whenever current flows. This magnetic field will induce a voltage in the second wire if it extends to it. This is how transformers function on a fundamental level. The primary's magnetic field induces a voltage in the secondary. This voltage is undesired and might be temporary when it comes from adjacent or nearby building wiring.

Elevators, HVAC systems (HVAC with variable frequency drives), fluorescent light ballasts, copiers, and computers are all examples of equipment that might produce inductive coupling.

Static electricity

Static electricity or electrostatic discharge (ESD) can generate electromagnetic fields over a wide frequency range, down to the low gigahertz region. The term ESD  event refers to the discharge current as well as the electromagnetic fields and corona effects that occur before to and during the discharge. ESD  causes a charge transfer between items with different electrostatic potentials to occur suddenly. ESD  causes a lot of high-frequency noise in electrical distributions.

Electrostatic discharges can destroy equipment and cause physical harm. Data corruption and device lockups are examples of device failures. Equipment damage or even death are examples of physical damage. To develop ESD  immunity that is meaningful,

The complete system, including direct discharges and fields, must be considered in the design.

A minimum voltage of roughly 3000V is required for a person to know that he or she is engaging in ESD,   Electrostatic discharges below the threshold of human perception, on the other hand, may contain enough energy to cause electronic devices to malfunction or be damaged. In fact, at these low voltage levels, the quicker beginning slope of the current waveform produced by ESD  events may make such discharges more harmful than ESD  events produced at higher voltage levels.

Depending on the environment, the voltage on the human body or moving objects might vary dramatically. In controlled humidity circumstances with solely antistatic or static dissipative materials, it can stay much below 5kV. In low humidity conditions with synthetic materials, it can vary from 5 kV to 15 kV. The device victim is in close proximity to an ESD  event, and the electromagnetic field formed by the discharge between the intruder and the receiver might upset or harm it.

External sources:

Lightning is the most prevalent cause of surges outside of a facility. While lightning may be uncommon in some locations, the damage it does to infrastructure can be devastating. Thunderstorms and lightning are more common in other areas.

Lightning can generate a surge by making direct contact with the facility's electrical system or, more typically, by initiating the surge onto a power or communication system via indirect or nearby lightning. Both of these circumstances have the potential to cause instant damage to the electrical system and/or linked loads.

Utility-initiated grid and capacitor bank switching are two more external drivers of surges. To help remove faults in the system, utilities may need to switch power supply to another source or temporarily interrupt the flow of electricity to their customers during grid operation. A line failure is frequently caused by a fallen tree branch or a small animal. When power is cut and then reconnected to customer loads, this causes surges.

During normal power system operation, power quality disruptions might be provided. Electric utilities generate power from a variety of sources and then distribute it to specified consumer grids. Electric utilities alter the distribution of power rather than continually adjusting the generating equipment of the electric utility since the equipment used to generate electricity performs most efficiently at a constant pace. When utilities switch power supply from one grid to another, power disturbances such as transients or spikes, as well as undervoltage and overvoltage circumstances, occur. These actions will introduce transients into the system, which could potentially spread to end-user equipment, causing damage or operational confusion.