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IEEE C62.43.1-2020 pdf free download
IEEE C62.43.1-2020 pdf free download.IEEE Guide for Surge Protectors and Surge Protective Circuits Used in Information and Communication Technology Circuits (ICT), Including Smart Grid Part 1 Applications.
Some surge conditions do not activate the voltage-limiting components of the SPD, but the surge can still damage equipment. The currents driven by these surges arc sometimes referred to as “sneak currents” because they are low-voltage surges that are said to sneak by the voltage-limiting component. Although sneak currents are low voltage and (usually) low current, they can have long duration. Sneak currents can cause electronic components and wiring to overheat, which could interrupt service or start a fire. Howcvcr, the current-limiting components of the SPD are intended to interrupt or reduce these currents.
The pertbrmance of an SPD’s overcurrent protection components during and after a surge is evaluated using the transition current and time-to-trip tests. SP[)s containing or requiring self-resetting current-limiting devices are evaluated by the test in IEEE Std C62.36 for ability to restore to quiescent state.
Some types of overcurrent protection devices, such as heat coils, do not reset once activated. Other types. such as PTC thermistors, reset automatically. A heat coil diverts the sneak current to ground by releasing a mechanism that permanently short-circuits the protected conductor to ground. (High currents can cause the series element of a heat coil to fuse, interrupting the current.). GDTs can also be equipped with a one-time shorting mechanism which operates under long-terni ac power contact conditions. On the other hand, a PTC thermistor reduces current (i.e., limits) by accumulating heat, which increases its resistance. When the voltage across the activated thermistor is substantially reduced, the thermistor cools and returns to a low-resistance condition, allowing normal circuit operation to resume.
AC life and impulse life tests are accelerated life tests that are meant to simulate the surge conditions SPDs might experience once installed. Note that some component degradation can be expected to occur during surge life testing. However, specifications for the SPD should properly anticipate component degradation. For instance, the dc-limiting voltage of GDTs and air gaps has a tendency to decrease as the number of applied surges increases. Therefore, these SPDs/SPCs typically have an initial dc-limiting voltage that is higher than the rated voltage of the protected circuit.
Because of this change in operating parameters of gap-type components with surge life discharges, the user sometimes makes compromises in performance of these protector types to achieve a desired “life span.” For instance, the dc-limiting voltage situation described here results in higher impulse-limiting voltages. In this case, a compromise is made to allow higher peak voltages to reach equipment for the gap-type components to achieve the desired life span.IEEE C62.43.1-2020 pdf free download.
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