Replacing a transformer with a lower %Z will have what effect on fault current downstream?

Replacing a transformer with a lower %Z (percentage impedance) will result in increased fault currents downstream. The percentage impedance of a transformer plays a critical role in determining how much current can flow when a fault occurs. A transformer with lower %Z has less impedance to oppose the fault current, which means that when a fault occurs, the transformer's ability to limit the flow of current is reduced.

In simpler terms, the lower the %Z, the less resistance there is to the flow of electrical current during a fault condition. Consequently, this allows more fault current to pass through the system, resulting in higher fault currents downstream. This phenomenon can lead to more severe effects in the electrical system, such as increased heat generation, which can damage equipment and pose serious safety hazards.

Understanding this relationship is crucial for electrical safety and system design, as it helps in determining appropriate transformer specifications to mitigate fault current levels and enhance overall system protection.