Table of Contents
What is MCOV of a surge arrester?
MCOV stands for the Maximum Continuous Operating Voltage. COV or UC stands for Continuous Operating Voltage. They represent the power frequency voltage that may be continuously applied to a surge arrester.
How do you calculate a surge arrester?
Selection of LA
- For 220KV side: Voltage rating = 1.1 × 220 × 0.8 = 193.6KV. Power frequency spark over voltage = 1.5 ×193.6 = 290.4KV.
- For 110KV side: Voltage rating = 1.1 × 110×0.8 = 96.8KV.
- For 66kV Side. Voltage rating = 1.1 × 66×0.8 = 58.08kV.
- For 11 KV side: Voltage rating = 1.1× 11×0.8 = 9.68KV.
How is SPD rating determined?
The peak surge current ratings of SPD are generally based on the sum of Line-neutral and Line-ground current.
- The peak surge current ratings of SPD are generally based on the sum of Line-neutral and Line-ground current.
- A peak ampere rating per phase.
How do surge arresters work?
A surge arrester works by diverting the extra voltage into the earth wire, rather than flowing through the electronic devices, while at the same time allowing the normal voltage to continue along its path.
How many types of surge arresters are there?
There are three classes of power system surge arresters: station-, intermediate-, and distribution-class. Station arresters provide the best protective levels but are more expensive.
What is the difference between surge arrester and surge protector?
There is also another type of electrical safety equipment similar to the surge arrester. The surge protector has the same function as a surge arrester but is used to protect domestic and consumer electrical equipment whereas the surge arrester is for large-scale protection (medium to high voltage).
Do I need a surge arrester?
The answer is yes, it’s necessary because power surges can happen any time and no one’s prepared for a powerful surge. Given how power surges can occur at any time, there’s no worry about electronic device damage with a surge protector.
How is MCOV calculated?
The continuous operating voltage is 13,800 divided by the square root of 3, or 7970 V. This is above the MCOV of 7,650 V for an arrester rated 9 kV.
How do you size an SPD?
The formula to determine this will depend on the type of system. For example, for a single-phase system (also called a split-phase system), the line-to-line voltage is divided by two. The result is the optimal amount of volts that the SPD should have for that system.
How do surge arresters fail?
In most scenarios, failure occurs due to dielectric breakdown, whereby the internal structure has deteriorated to the point where the arrester is unable to withstand applied voltage, whether normal system voltage, temporary power frequency overvoltage (e.g. following external line faults or switching) or lightning or …
What is Type 2 surge arrester?
The Type 2 Surge Protection Devices are the main protection system for all low voltage electrical installations. Installed in each electrical switchboard, it prevents the spread of any overvoltages in the electrical installations and protects the loads. Type 2 SPD is characterized by an 8/20 µs current wave.
How does a surge arrestor work?
Is surge arrester same as lightning arrester?
While most people believe that a lightning arrester and surge arrester are the same, they are different. The former one is installed outdoors whereas the latter one is installed indoors. However, both of them keep your electrical appliances safe from accidents.
What is the mcov of the arrester?
The arrester MCOV is shown in group 2 of table 1 and given in kV (1 kV=1000 volts). This voltage is determined during the course of testing the arrester to IEEE standard C62.11 and is the most important voltage rating of the arrester.
What is discharge voltage of an arrester?
This discharge voltage represents the response of an arrester to a slow-rising surge generated within the power systems during breaker or switch operations. Probably the most widely used table in arrester datasheets is the arrester rating selection table.
What is a gas discharge arrestor on a surge protector?
Inside a surge protector with line-conditioning chokes Another common surge protection device is a gas discharge arrestor, or gas tube. These tubes do the same job as an MOV — they divert the extra current from the hot line to the ground line. They do this by using an inert gas as the conductor between the two lines.
What are GDT surge arrestors used for?
Gas Discharge Tube (GDT) Surge Arrestors. Gas Discharge Tubes (GDTs) are used to protect personnel and sensitive equipment from hazardous transient voltages. Bourns® GDTs are used in primary and secondary applications and can withstand multiple applications of high surge current energy in excess of 25 KA.