Arcteq Generator Commander, Инструкция по эксплуатации

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5.4.27 Generator/transformer differential protection (Idb>/Idi>/I0dHV>/I0dLV>; 87T/
87N/87G)
The generator/transformer differential function is used for protecting the following power
transformers: two-winding transformers, and to some extent three-winding and two-winding
transformers that have double outputs and a summing application. This function can also be used for
protecting generators.
Figure. 5.4.27 - 127. Differential protection function can be used for protecting transformers, generators and both at the same
time.
Power transformers are seen in electric power generation, transmission, and distribution. They are also
part of application networks for a wide range of purposes (eg. power and voltage levels). The most
common use for a transformer is (as the name implies) to transform alternating voltage from one
voltage level to another. What is common for all transformers is that they are a crucial and one of the
most important single components in a network because a transformer's failure affects a wide area in
the network. While transformers do not have many moving parts (apart from tap changers), their
electric and mechanical properties are far from being simple.
When designing transformer protection it is usual to consider the transformer's usage as well as the
power level it transforms. This is because the economical aspect becomes more significant as the size
of the transformer increases, and the applied protection should be in line with the cost of the
transformer. For example, there is little point in installing a high-level multifunction transformer device
into a distribution transformer of a few kVA that feeds a handful of farms in a rural area network.
Similarly, it is pointless to have nothing but fuses protecting a transmission transformer of a few
hundred MVA that feeds entire cities.
When designing transformer protection one should consider which protection elements are needed to
apply sufficient protection. The following table gives a rough idea what protection methods and
elements as well as risks exist for the different types of transformers. Overlooking these points when
designing transformers increase the risk of costly problems with the transformer.
Genera Generattor Commander or Commander
Instruction manual
Version: 2.07
© Arcteq Relays Ltd
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