The main products

Spare parts spare parts, the DCS control system of PLC system and the robot system spare parts,

Brand advantage: Allen Bradley, BentlyNevada, ABB, Emerson Ovation, Honeywell DCS, Rockwell ICS Triplex, FOXBORO, Schneider PLC, GE Fanuc, Motorola, HIMA, TRICONEX, Prosoft etc. Various kinds of imported industrial parts

VME-7807RC General electric module

Group of connection of a three-phase transformer s1, s2, s3 Factor s1 defines the connection of the three phase windings 1. Factors s2 and s3 define the group of connection of windings 2 and windings 3 respectively, i.e. they define firstly how the windings are connected and secondly their phase-angle referred to windings 1. The following arrangement is an example for two generators with a common step-up transformer:The factors are correspondingly: s1 = Y s2 = d11 s3 = d11 Factors s2 and s3 are defined according to their phase shift in relation to the HV side, i.e. to windings 1.

Compensation for group of connection Phase-to-phase currents are measured in order to compare primary and secondary currents without regard to the circuit of the transformer. The combination of these currents internally in the protection takes account, however, of their phase relationships. The relationships between the current vectors for different groups of connection can be seen from the following illustrations. For example, for a Yd5 connected transformer

Y-connected primary
Delta-connected secondary
Phase-angle between the currents of the same phase on both sides 5 x 30° = 150°

Application

 General purpose current function (over and under) for
phase fault protection
back-up protection
earth fault protection or for monitoring a current minimum. B. Features
insensitive to DC component
insensitive to harmonics
single or three-phase measurement
maximum respectively minimum value detection in the threephase mode
detection of inrush currents. C. Inputs and outputs I. C.t./v.t. inputs:
Current II. Binary inputs:
Blocking III. Binary outputs:
pick-up
tripping IV. Measurements:
current amplitude.Explanation of parameters: RunOnCPU defines the processing unit which runs the function. ParSet 4..1 Parameter for determining in which set of parameters a particular function is active (see Section 5.11.). Trip 01-08 defines the tripping channel activated by the tripping O/P of the function (matrix tripping logic). Trip 09-16 corresponds to Trip 01-08 (providing tripping unit fitted). Trip 17-24 corresponds to Trip 01-08 (providing tripping unit fitted).

Trip 25-32 corresponds to Trip 01-08 (providing tripping unit fitted). Delay Time between the function picking up and tripping. I-Setting Pick-up current setting. Setting restrictions:
not > 2.5 IN when supplied from metering cores
not < 0.2 IN when supplied from protection cores. MaxMin defines operation as overcurrent or undercurrent or with inrush blocking. Settings:
MAX: overcurrent
MIN: undercurrent
MAX-Inrush: 1 phase exceeds the MAX setting and blocks for an inrush current.