SPD Specific Disconnector (SSD), low voltage distribution system SPD special backup protection device, can withstand the expected surge current at the installation of the protected surge protector, and is able to interrupt the SPD failure due to the SPD through the frequency current of the device, and has the characteristics of the frequency of the small current action, also known as SPD backup protector or SCB.
Usually SPD backup protection will use fuses or circuit breakers, however, because the surge resistance of fuses and circuit breakers is positively correlated with the rated current value, which means that in order to pass the surge test, the rated current value of them is required to be relatively large, such as through the test of 20 kA (In) and 40 kA (Imax), the ordinary gL / gG fuses require 125 For example, through the test of 20 kA (In) and 40 kA (Imax), ordinary gL / gG fuses need 125 A, and ordinary circuit breakers need 63 A – 100 A. The operating current of 125 A fuses is as high as 625 A for 5 s, and ordinary circuit breakers that meet the same surge test are also about the same value. This characteristic leads to a blind spot in the backup protection of SPDs with ordinary fuses and circuit breakers. Typically, the distribution system has a small capacity, and in the event of a short-circuit, the fuses of the SPDs do not actuate, so that the SPDs will catch fire quickly. Most SPD fires are caused by this mismatch, where the backup protection does not operate.
EYZAO SSDs are characterized by being able to pass a surge test matched to the SPD and, at the same time, can be activated at a low frequency current, typically around 3 A, ensuring that the protection is activated before the SPD catches fire. SSDs have a higher surge tolerance, lower frequency current activation characteristics, and are characterized by their small size, high sensitivity, and high interrupting capacity.
The EYZAO SSDs are designed to perfectly match the EYZAO SPDs for perfect protection, and the EYZAO SSDs are designed in a single-piece, free-standing configuration for flexible pairing.
