Siemens 7SR242 Duobias - Inverse Time (24 IT)

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7SR242 Duobias Commissioning & Maintenance Guide

2.12.2 inverse time (24IT)

The inverse V/f element should be tested at each of the points specified by settings that constitute the overall

inverse characteristics.

Setting

(xVn)

Setting

(volts)

Hysteresis

(%)

Calculated

D.O.

(volts)

DTL

Setting

(sec)

P.U.

Volts

D.O.

Volts

Operate

Time

NOTES

Setting

(xVn)

Setting

(volts)

DTL

Setting

(sec)

Operate

Time

NOTES

X1 Y1

X2 Y2

X3 Y3

X4 Y4

X5 Y5

X6 Y6

Main Page

Document Release History1
Software Revision History1
Table of Contents2
Contents2
Section 1: Common Functions5
Overview5
Before Testing5
Safety5
Sequence of Tests5
Test Equipment6
Precautions6
Applying Settings7
Tests8
Inspection8
Secondary Injection Tests8
Primary Injection Tests8
Putting into Service8
AC Energising Quantities9
Binary Inputs10
Binary Outputs11
Relay Case Shorting Contacts11
Section 2: Protection Functions12
Biased Differential (87BD, 87HS)14
Secondary Injection Testing14
Figure 2-1 Biased Differential14
Figure 2-2 Secondary Injection Using a Variac15
Primary Injection Testing17
Phase Overcurrent (50, 51)18
Figure 2-3 Phase Overcurrent18
Definite Time Overcurrent (50)19
Inverse Time Overcurrent (51)19
Derived Earth Fault (50N,51N)21
Figure 2-4 Measured Earth Fault21
Definite Time Overcurrent (50N)22
Inverse Time Overcurrent (51N)22
ANSI Reset23
Measured Earth Fault (50G, 51G)24
Figure 2-5 Measured Earth Fault24
Definite Time Overcurrent (50G)25
Inverse Time Overcurrent (51G)25
ANSI Reset26
Restricted Earth Fault (64H)27
Figure 2-6 Restricted Earth Fault27
Open Circuit (46BC)29
Figure 2-7 Open Circuit29
Negative Phase Sequence Overcurrent (46NPS)31
Figure 2-8 Negative Phase Sequence Overcurrent31
Definite Time NPS Overcurrent (46DT)32
Inverse Time NPS Overcurrent (46IT)32
Undercurrent (37, 37G)34
37-N Elements34
Figure 2-9 Undercurrent34
Elements35
Thermal Overload (49)36
Figure 2-10 Thermal Overload36
Under/Over Voltage (27/59)38
Figure 2-11 Phase Under/Over Voltage38
Undervoltage Guard (27/59UVG)40
Neutral over Voltage (59N)41
Figure 2-12 Neutral Overvoltage41
Definite Time (59NDT)42
Inverse Time (59NIT)42
Under/Over Frequency (81)43
Figure 2-13 Under/Over Frequency43
Overfluxing (24)45
Definite Time (24DT)45
Figure 2-14 Under/Over Frequency45
Inverse Time (24IT)46
Section 3: Supervision Functions47
CB Fail (50BF)47
Figure 3-1 CB Fail47
Trip/Close Circuit Supervision (74TCS, 74CCS)49
Figure 3-2 Trip Circuit Supervision49
Magnetising Inrush Detector (81HBL2)50
Figure 3-3 Magnetising Inrush Detector50
Overfluxing Detector (81HBL5)52
Figure 3-4 Magnetising Inrush Detector52
Section 4: Control & Logic Functions53
Quick Logic53
Section 5: Testing and Maintenance54
Periodic Tests54
Maintenance54
Troubleshooting54
Defect Report Form56

Siemens 7SR242 Duobias - Inverse Time (24 IT)

Table of Contents

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