By double clicking on the “Protection unit” element, its properties window will open. In tab “General” the user can edit general information about the protection unit, add a current transformer and breaker data. EA – PSM will already provide recommended values for the breaker, in blue colored lines.
In the “Equipment” tab current transformers, disconnectors, contactors, grounding switches, electricity meters and indicators can be added and modified. To add an element to the breaker, choose the wanted breaker element and click the button “Add” at the bottom part of the window.
The current transformer tab is designed to calculate ALF value, which is “Accuracy limiting factor” of the transformer. However, properties that will be specified for the current transformer, is not going to affect trip unit operation in any way. Explanation of the current transformer parameters are provided below:
CT type – current transformer type (name). If it is 5P20, then 5P is accuracy class and 20 is accuracy limiting factor (ALF). This means that when current is less than “20 * In “(In is nominal current) then accuracy is 5%.
Coefficient – is current transformer ratio.
PN – is current transformer burden at which rated accuracy of the transformer is reached.
IED load – trip unit winding resistance.
Explanation of the breaker properties are provided below:
IN – nominal current.
UN – nominal voltage.
IKmax – maximum short circuit current.
Ip – peak short circuit current.
Idc – DC component of the short circuit current.
IB – breaking current.
The order of the equipment (including added protections) can be managed in the “Attachment order” tab. User may click the arrow buttons or drag the equipment items up or down. Applying the properties will also change the breaker’s graphic depicted in the scheme.
In the “Short Circuit” tab filtered short circuit results can be seen. Only short circuits, which flow through the selected protection are shown in the table. If asymmetrical short circuit is selected (K2, K1, K1.1), the user will be able to analyze vector diagrams by pressing “Vectors” button.
In the “Protection” tab circuit breakers and relay protection can be selected and edited by clicking “Add protection” button. “Remove” button will delete selected protection. “Export” button will form a report with the short circuit results and the protection device parameters.
