GE Multilin L30 Line Current Differential System 5-75 SETTINGS 5.1 OVERVIEW5b) CT/VT MODULE CONFIGURATIONCT and VT input channels are contained in CT/VT modules. The type of input channel can be phase/neutral/other voltage,phase/ground current, or sensitive ground current. The CT/VT modules calculate total waveform RMS levels, fundamentalfrequency phasors, symmetrical components and harmonics for voltage or current, as allowed by the hardware in eachchannel. These modules may calculate other parameters as directed by the CPU module.A CT/VT module contains up to eight input channels, numbered 1 through 8. The channel numbering corresponds to themodule terminal numbering 1 through 8 and is arranged as follows: Channels 1, 2, 3 and 4 are always provided as a group,hereafter called a “bank,” and all four are either current or voltage, as are channels 5, 6, 7 and 8. Channels 1, 2, 3 and 5, 6,7 are arranged as phase A, B and C respectively. Channels 4 and 8 are either another current or voltage.Banks are ordered sequentially from the block of lower-numbered channels to the block of higher-numbered channels, andfrom the CT/VT module with the lowest slot position letter to the module with the highest slot position letter, as follows:The UR platform allows for a maximum of three sets of three-phase voltages and six sets of three-phase currents. Theresult of these restrictions leads to the maximum number of CT/VT modules in a chassis to three. The maximum number ofsources is six. A summary of CT/VT module configurations is shown below.c) CT/VT INPUT CHANNEL CONFIGURATIONUpon relay startup, configuration settings for every bank of current or voltage input channels in the relay are automaticallygenerated from the order code. Within each bank, a channel identification label is automatically assigned to each bank ofchannels in a given product. The bank naming convention is based on the physical location of the channels, required by theuser to know how to connect the relay to external circuits. Bank identification consists of the letter designation of the slot inwhich the CT/VT module is mounted as the first character, followed by numbers indicating the channel, either 1 or 5. Seethe HardFiber instruction manual for designations of HardFiber voltage and current banks.For three-phase channel sets, the number of the lowest numbered channel identifies the set. For example, F1 representsthe three-phase channel set of F1/F2/F3, where F is the slot letter and 1 is the first channel of the set of three channels.Upon startup, the CPU configures the settings required to characterize the current and voltage inputs, and will display themin the appropriate section in the sequence of the banks (as described above) as follows for a maximum configuration: F1,F5, L1, L5, S1, and S5.ITEM MAXIMUM NUMBERCT/VT Module 1CT Bank (3 phase channels, 1 ground channel) 2VT Bank (3 phase channels, 1 auxiliary channel) 1
