用于短路保护的保护继电器以及许多其他类型的保护继电器也通过由多个组合的电力变压器提供给它们的电压和/或电流来操作，以便对要被保护的设备组件进行操作。通过对这两个比例进行特定或相对的修改，故障将其类型，可视性和位置标示给保护继电器。对于每个失败的地点和类型，这些比例都有一些独特的差异，在这里可以使用不同类型的保护 – 中继设备，其中每一个设计都是为了确定一个特定的差异，然后对它进行操作。这些比例中存在的其他差异比人们怀疑的要多。在以下几个方面，每个比例的差异是可能的：
How do Protective Relay Systems Operate
Up till now, we’ve dealt with the protective relays themselves in a more impersonal approach, informing what protective relay is devoid of any regard to how they do it. This remarkable part of the report of relaying system will be mentioned to in much more information. However, with the intention of round out this basic consideration of relaying and to plan for what is yet ahead, some description is in order right here.
Protective relays implemented for short-circuit protection, and lots of various other types also, operate by the voltage and/or current supplied to them by power transformers linked in numerous combinations to the device component that is to be protected. By specific or relative modifications in these two proportions, failures signal their type, visibility, and location to the protective relays. For each location and type of failing, there is some unique difference in these proportions, and there are different types of protection-relaying devices accessible here, each of which is designed to identify a specific difference and to operate in reply to it. Additional differences present in these proportions than one may suspect. Differences in each proportion are possible in several of the following:
Rate of change.
Harmonics or wave shape.
Direction or order of change.
Then, when both current and voltage are considered in combination, or relative to comparable amounts at various places, I started to comprehend the resources offered for discriminatory functions. It is a privileged situation that, although relays have enforced the concern of electric-power-system failure, it is simultaneously offering me with a way to combat.