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Siemens 7SR11 Manual

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7SR11 and 7SR12
Description of Operation
Document Release History
This document is issue 2012/02. The list of revisions up to and including this issue is:
2012/02
AC auxiliary power supply added
2012/01
Software Maintenance
2011/06
Software Maintenance
2010/04
Amendments following PLM review
2010/02
Document reformat due to rebrand
2009/09
Format and relay fascia revised.
2009/04
First Issue
Software Revision History
2012/01
7SR11 2436H80003 R2a-2a
7SR12 2436H80004 R2a-2a
2011/06
7SR11 2436H80003 R2-2
7SR12 2436H80004 R2-2
2009/04
2436H80003R1g-1c 7SR11
2436H80004R1g-1c 7SR12
The copyright and other intellectual property rights in this document, and in any model or article produced from it
(and including any registered or unregistered design rights) are the property of Siemens Protection Devices
Limited. No part of this document shall be reproduced or modified or stored in another form, in any data retrieval
system, without the permission of Siemens Protection Devices Limited, nor shall any model or article be
reproduced from this document unless Siemens Protection Devices Limited consent.
While the information and guidance given in this document is believed to be correct, no liability shall be accepted
for any loss or damage caused by any error or omission, whether such error or omission is the result of
negligence or any other cause. Any and all such liability is disclaimed.
©2012 Siemens Protection Devices Limited
7SR11 & 7SR12 Description Of Operation
Software Maintenance
Software Maintenance
First Release

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  • Page 1 Limited. No part of this document shall be reproduced or modified or stored in another form, in any data retrieval system, without the permission of Siemens Protection Devices Limited, nor shall any model or article be reproduced from this document unless Siemens Protection Devices Limited consent.

  • Page 2: Table Of Contents

    7SR11 & 7SR12 Description Of Operation Contents Section 1: Introduction ............................. 7 1.1 Current Transformer Circuits........................7 1.2 External Resistors ........................... 7 1.3 Front Cover ............................. 7 Section 2: Hardware Description..........................15 2.1 General ..............................15 2.2 Case..............................15 2.3 Front Cover ............................16 2.4 Power Supply Unit (PSU)........................
  • Page 3 5.1 Circuit Breaker Failure (50BF) ......................64 5.2 VT Supervision (60VTS) – 7SR1205 & 7SR1206 ................. 65 5.3 CT Supervision (60CTS) ........................67 5.3.1 60CTS for 7SR11 (60CTS-I for 7SR12) .................. 67 5.3.2 60CTS for 7SR12........................67 5.4 Broken Conductor (46BC)........................68 5.5 Trip/ Close Circuit Supervision (74TCS &...
  • Page 4 Figure 1-35 Logic Diagram: 7SR11 SEF Instantaneous Element ................38 Figure 1-36 Logic Diagram: 7SR12 SEF Instantaneous Element ................39 Figure 1-37 Logic Diagram: 7SR11 SEF Time Delayed Element (51SEF) ............40 Figure 1-38 Logic Diagram: 7SR12 SEF Time Delayed Element (51SEF) ............41 Figure 1-39 Logic Diagram: High Impedance REF (64H) ..................
  • Page 5 Figure 4-5 Logic Diagram: Circuit Breaker Fail Protection (50BF) ................. 64 Figure 4-6 Logic Diagram: VT Supervision Function (60VTS) ................66 Figure 4-7 Logic Diagram: CT Supervision Function (60CTS) – 7SR11 ..............67 Figure 4-9 Logic Diagram: CT Supervision Function (60CTS) – 7SR12 ..............68 Figure 4-10 Logic Diagram: Broken Conductor Function (46BC)................
  • Page 6 7SR11 & 7SR12 Description Of Operation ©2012 Siemens Protection Devices Limited Chapter 1 Page 6 of 76...

  • Page 7: Section 1: Introduction

    7SR11 & 7SR12 Description Of Operation Section 1: Introduction This manual is applicable to the following relays: • 7SR11 Overcurrent and Earth Fault Relay • 7SR12 Directional Overcurrent and Directional Earth Fault Relay The ‘Ordering Option’ Tables summarise the features available in each model General Safety Precautions 1.1 Current Transformer Circuits...

  • Page 8: Table 1-1 7Sr11 Ordering Options

    7SR11 & 7SR12 Description Of Operation Table 1-1 7SR11 Ordering Options □ □ □ □ □ 7 S R 1 1 0 A 1 2 - Nondirectional O/C Relay ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ | | |...

  • Page 9: Figure 1-1 Functional Diagram Of 7Sr1101-1_A12-_Ca0 Relay

    7SR11 & 7SR12 Description Of Operation 7SR1101-1_A12-_CA0 (x2) (x2) (x2) I(EF) (x3) (x3) Figure 1-1 Functional Diagram of 7SR1101-1_A12-_CA0 Relay Figure 1-2 Functional Diagram of 7SR1101-3_A12-_CA0 Relay Figure 1-3 Functional Diagram of 7SR1103-1_A12-_DA0 Relay Figure 1-4 Functional Diagram of 7SR1103-3_A12-_DA0 Relay ©2012 Siemens Protection Devices Limited...

  • Page 10: Figure 1-5 Connections Diagram For 7Sr11 Relay

    Shows contacts internal to relay case BO 2 assembly. Contacts close when the relay chassis is withdrawn from case BO 3 BO 4 BO 5 Figure 1-5 Connections Diagram for 7SR11 Relay ©2012 Siemens Protection Devices Limited Chapter 1 Page 10 of 76...

  • Page 11: Table 1-2 7Sr12 Ordering Options

    7SR11 & 7SR12 Description Of Operation Table 1-2 7SR12 Ordering Options □ □ □ □ □ □ 7 S R 1 2 0 Directional O/C Relay ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ | | | Directional | | |...

  • Page 12: Figure 1-6 Functional Diagram Of 7Sr1204-2_A12-_Ca0 Relay

    7SR11 & 7SR12 Description Of Operation Figure 1-6 Functional Diagram of 7SR1204-2_A12-_CA0 Relay 7SR1204-4_A12-_CA0 67/50 67/51 (x2) (x4) (x4) (x4) (x4) (x2) (x4) (x4) (x3) (x3) Figure 1-7 Functional Diagram of 7SR1204-4_A12-_CA0 Relay ©2012 Siemens Protection Devices Limited Chapter 1 Page 12 of 76...

  • Page 13: Figure 1-8 Functional Diagram Of 7Sr1205-2_A12-_Da0 Relay

    7SR11 & 7SR12 Description Of Operation 7SR1205-2_A12-_DA0 (x2) (x4) (x4) (x2) (x4) (x4) (x2) (x2) (x4) (x4) (x4) (x4) (x4) (x4) (x4) (x4) (x2) (x4) (x3) (x3) NOTE: The use of some functions (x4) are mutually exclusive Figure 1-8 Functional Diagram of 7SR1205-2_A12-_DA0 Relay...

  • Page 14: Figure 1-10 Connections Diagram For 7Sr12 Relay

    7SR11 & 7SR12 Description Of Operation Figure 1-10 Connections Diagram for 7SR12 Relay ©2012 Siemens Protection Devices Limited Chapter 1 Page 14 of 76...

  • Page 15: Section 2: Hardware Description

    7SR11 & 7SR12 Description Of Operation Section 2: Hardware Description General The structure of the relay is based upon the Reyrolle Compact hardware platform. The relays are supplied in a size E4 case (where 1 x E = width of approx. 26mm). The hardware design provides commonality between products and components across the Reyrolle Compact range of relays.

  • Page 16: Front Cover

    The rear terminal blocks comprise M4 female terminals for wire connections. Each terminal can accept two 4mm crimps. Figure 1-12 7SR11 Rear view of 7SR11 Relay Located at the top rear of the case is a screw clamp earthing point, this must be connected to terminal 28 and directly to the main panel earth.

  • Page 17: Power Supply Unit (Psu)

    7SR11 & 7SR12 Description Of Operation Figure 1-14 Relay with standard transparent cover If access is required to view the menus without removing the cover, an alternative transparent cover with push ▼ TEST/RESET► buttons may be ordered. With the cover in place the user will only has access to the buttons, allowing all areas of the menu system to be viewed, but preventing setting changes and control actions.

  • Page 18: Operator Interface/ Fascia

    7SR11 & 7SR12 Description Of Operation Operator Interface/ Fascia The operator interface is designed to provide a user-friendly method of controlling, entering settings and retrieving data from the relay. Figure 1-16 Relay with Transparent cover removed The fascia is an integral part of the relay. Handles are located at each side of the relay which allow it to be withdrawn from the relay case.

  • Page 19: Figure 1-18 Close Up Of Relay Identifier

    7SR11 & 7SR12 Description Of Operation For safety reasons the following symbols are displayed on the fascia Liquid Crystal Display (LCD) A 4 line by 20-character alpha-numeric liquid crystal display indicates settings, instrumentation, fault data and control commands. To conserve power the display backlighting is extinguished when no buttons are pressed for a user defined period.
  • Page 20 7SR11 & 7SR12 Description Of Operation LCD Indication General Alarms are user defined text messages displayed on the LCD when mapped to binary or virtual inputs. Up to six general alarms of 16 characters can be programmed, each triggered from one or more input. Each general alarm will also generate an event.

  • Page 21: Current Inputs

    7SR11 & 7SR12 Description Of Operation Figure 1-19 LED Indication Label Current Inputs Either one or four current inputs are provided on the Analogue Input module. Terminals are available for both 1A and 5A inputs. Two types of current input are incorporated within the relay, one type is used for phase fault and earth fault protection, while the other is used for sensitive earth fault (SEF) and restricted earth fault (REF).

  • Page 22: Binary Outputs (Output Relays)

    7SR11 & 7SR12 Description Of Operation Each input may be logically inverted to facilitate integration of the relay within the user scheme. When inverted the relay indicates that the BI is energised when no voltage is applied. Inversion occurs before the PU & DO time delay, see fig.

  • Page 23: 2.10 Virtual Input/Outputs

    7SR11 & 7SR12 Description Of Operation Notes on Self Reset Outputs Self reset operation has a minimum reset time of 100ms With a failed breaker condition the relay may remain operated until current flow is interrupted by an upstream device. When the current is removed the relay will then reset and attempt to interrupt trip coil current flowing via its output contact.

  • Page 24: 2.11 Self Monitoring

    7SR11 & 7SR12 Description Of Operation 2.11 Self Monitoring The relay incorporates a number of self-monitoring features. Each of these features can initiate a controlled reset recovery sequence. Supervision includes a power supply watchdog, code execution watchdog, memory checks by checksum and processor/ADC health checks.

  • Page 25: Figure 1-23 Start-Up Events

    7SR11 & 7SR12 Description Of Operation Figure 1-23 Start-up Events ©2012 Siemens Protection Devices Limited Chapter 1 Page 25 of 76...

  • Page 26: Section 3: Protection Functions

    7SR11 & 7SR12 Description Of Operation Section 3: Protection Functions Current Protection: Phase Overcurrent (67, 51, 50) All phase overcurrent elements have a common setting for the 50 elements and 51 elements to measure either fundamental frequency RMS or True RMS current:...

  • Page 27: Instantaneous Overcurrent Protection (50)

    Figure 1-24 Logic Diagram: Directional Overcurrent Element (67) 3.1.2 Instantaneous Overcurrent Protection (50) Two Instantaneous overcurrent elements are provided in the 7SR11 relay and four elements are provided in the 7SR12 relay. 50-1, 50-2, (50-3 & 50-4 – 7SR12) Each instantaneous element (50-n) has independent settings. 50-n Setting for pick-up current and 50-n Delay follower time delay.

  • Page 28: Time Delayed Overcurrent Protection (51)

    Figure 1-25 Logic Diagram: Instantaneous Over-current Element 3.1.3 Time Delayed Overcurrent Protection (51) Two time delayed overcurrent elements are provided in the 7SR11 relay and four elements are provided in the 7SR12 relay. 51-1, 51-2, (51-3 & 51-4 – 7SR12) 51-n Setting sets the pick-up current level.

  • Page 29: Figure 1-26 Logic Diagram: Time Delayed Overcurrent Element

    7SR11 & 7SR12 Description Of Operation A minimum operate time for the characteristic can be set using 51-n Min. Operate Time setting. A fixed additional operate time can be added to the characteristic using 51-n Follower DTL setting. Where directional elements are present the direction of operation can be set using 51-n Dir. Control setting.

  • Page 30: Current Protection: Voltage Controlled Overcurrent (51V) - 7Sr12

    7SR11 & 7SR12 Description Of Operation 3.1.4 Current Protection: Voltage Controlled Overcurrent (51V) - 7SR12 Voltage controlled overcurrent is only available in relays with four current inputs. Each shaped overcurrent element 51-n Setting can be independently controlled by the level of measured (control) input voltage.

  • Page 31: Current Protection: Derived Earth Fault (67N, 51N, 50N)

    7SR11 & 7SR12 Description Of Operation Current Protection: Derived Earth Fault (67N, 51N, 50N) The earth current is derived by calculating the sum of the measured line currents. The elements measure the fundamental frequency RMS current. 3.2.1 Directional Control of Derived Earth Fault Protection (67N) – 7SR12 The directional element produces forward and reverse outputs for use with derived earth fault elements.

  • Page 32: Instantaneous Derived Earth Fault Protection (50N)

    Figure 1-29 Logic Diagram: Derived Instantaneous Earth Fault Element 3.2.3 Time Delayed Derived Earth Fault Protection (51N) Two time delayed derived earth fault elements are provided in the 7SR11 relay and four elements are provided in the 7SR12 relay. 51N-1, 51N-2, (51N-3 & 51N-4 – 7SR12) 51N-n Setting sets the pick-up current level.

  • Page 33: Figure 1-30 Logic Diagram: Derived Time Delayed Earth Fault Protection

    7SR11 & 7SR12 Description Of Operation Char. When definite time lag (DTL) is selected the time multiplier is not applied and the 51N-n Delay (DTL) setting is used instead. The 51-n Reset setting can apply a definite time delayed reset, or when the operation is configured as an IEC or ANSI or user characteristic if the reset is selected as IEC/ANSI (DECAYING) reset the associated reset curve will be used.

  • Page 34: Current Protection: Measured Earth Fault (67G, 51G, 50G)

    7SR11 & 7SR12 Description Of Operation Current Protection: Measured Earth Fault (67G, 51G, 50G) The earth current is measured directly via a dedicated current analogue input, IL4. All measured earth fault elements have a common setting to measure either fundamental frequency RMS or True...

  • Page 35: Instantaneous Measured Earth Fault Protection (50G)

    7SR11 & 7SR12 Description Of Operation 3.3.2 Instantaneous Measured Earth Fault Protection (50G) Two instantaneous derived earth fault elements are provided in the 7SR11 relay and four elements are provided in the 7SR12 relay. 50G-1, 50G-2, (50G-3 & 50G-4 – 7SR12) Each instantaneous element has independent settings for pick-up current 50G-n Setting and a follower time delay 50G-n Delay.

  • Page 36: Time Delayed Measured Earth Fault Protection (51G)

    7SR11 & 7SR12 Description Of Operation 3.3.3 Time Delayed Measured Earth Fault Protection (51G) Two instantaneous derived earth fault elements are provided in the 7SR11 relay and four elements are provided in the 7SR12 relay. 51G-1, 51G-2, (51G-3 & 51G-4 – 7SR12) 51G-n Setting sets the pick-up current level.

  • Page 37: Current Protection: Sensitive Earth Fault (67Sef, 51Sef, 50Sef)

    7SR11 & 7SR12 Description Of Operation Current Protection: Sensitive Earth Fault (67SEF, 51SEF, 50SEF) Current for the Sensitive Earth Fault (SEF) elements is measured directly via a dedicated current analogue input which requires different hardware that must be specially ordered. SEF elements measure the fundamental frequency RMS current.

  • Page 38: Instantaneous Sensitive Earth Fault Protection (50Sef)

    Figure 1-34 Logic Diagram: SEF Directional Element (67SEF) 3.4.2 Instantaneous Sensitive Earth Fault Protection (50SEF) Two sensitive earth fault elements are provided in the 7SR11 relay and four elements are provided in the 7SR12 relay. 50SEF-1, 50SEF-2, (50SEF-3 & 50SEF-4– 7SR12) Each instantaneous element has independent settings for pick-up current 50SEF-n Setting and a follower time delay 50SEF-n Delay.

  • Page 39: Figure 1-36 Logic Diagram: 7Sr12 Sef Instantaneous Element

    7SR11 & 7SR12 Description Of Operation & & VT Fail 50SEF-n Dir En & & 67SEF Fwd & 67SEF Rev Wattmetric Block cos(θ-θ AUTORECLOSE = 50SEF-n & & = Delayed 50SEF-n Dir En Wattmetric Block cos(θ-θ Figure 1-36 Logic Diagram: 7SR12 SEF Instantaneous Element ©2012 Siemens Protection Devices Limited...

  • Page 40: Time Delayed Sensitive Earth Fault Protection (51Sef)

    7SR11 & 7SR12 Description Of Operation 3.4.3 Time Delayed Sensitive Earth Fault Protection (51SEF) Two sensitive earth fault elements are provided in the 7SR11 relay and four elements are provided in the 7SR12 relay. 51SEF-1, 51SEF-2, (51SEF-3 & 51SEF-4– 7SR12) 51SEF-n Setting sets the pick-up current level.

  • Page 41: Figure 1-38 Logic Diagram: 7Sr12 Sef Time Delayed Element (51Sef)

    7SR11 & 7SR12 Description Of Operation Figure 1-38 Logic Diagram: 7SR12 SEF Time Delayed Element (51SEF) ©2012 Siemens Protection Devices Limited Chapter 1 Page 41 of 76...

  • Page 42: Current Protection: High Impedance Restricted Earth Fault - (64H)

    7SR11 & 7SR12 Description Of Operation Current Protection: High Impedance Restricted Earth Fault - (64H) One high impedance Restricted Earth Fault (REF) element is provided 64H-1. The relay utilises fundamental current measurement values for this function. The single phase current input is derived from the residual output of line/neutral CTs connected in parallel. An external stabilising resistor must be connected in series with this input to ensure that this element provides a high impedance path.

  • Page 43: Current Protection: Negative Phase Sequence Overcurrent - (46Nps)

    7SR11 & 7SR12 Description Of Operation Cold Load Enabled Disabled Inhibit Cold Load CB Open Pick-up Time CB Closed & & Open Drop-off Time See Delayed Overcurrent & (51-n) Closed 51c-n Setting 51c-n Charact 51c-n Time Mult 51c-n Delay (DTL) Reduced 51c-n Min.

  • Page 44: Current Protection: Under-Current (37)

    7SR11 & 7SR12 Description Of Operation 46IT Setting 46IT Element 46IT Char 46IT Time Mult Enabled 46IT Delay (DTL) Disabled 46IT Reset & Pickup General Pickup Inhibit 46IT trip 46IT General Pickup 46DT Element 46DT Setting Enabled 46DT Delay Disabled >...

  • Page 45: Current Protection: Thermal Overload (49)

    7SR11 & 7SR12 Description Of Operation Figure 1-43 Logic Diagram: Earth Current Inputs Undercurrent Detector (37G) Figure 1-44 Logic Diagram: Sensitive Earth Current Inputs Undercurrent Detector (37SEF) Current Protection: Thermal Overload (49) The relay provides a thermal overload suitable for the protection of static plant. Phase segregated elements are provided.

  • Page 46: Current Protection: Line Check 50Lc, 50G Lc And 50Sef Lc - Only Software Option 'C

    7SR11 & 7SR12 Description Of Operation × θ 100% θ Where: θF = final thermal state before disconnection of device 49 Overload Setting I is expressed as a multiple of the relay nominal current and is equivalent to the factor k.

  • Page 47: Voltage Protection: Phase Under/Over Voltage (27/59) - 7Sr12

    7SR11 & 7SR12 Description Of Operation Figure 1-47 Logic Diagram: 50SEF Line Check Elements (50SEF LC) Figure 1-48 Logic Diagram: 50 Line Check Elements (50LC) 3.11 Voltage Protection: Phase Under/Over Voltage (27/59) – 7SR12 In total four under/over voltage elements are provided 27/59-1, 27/59-2, 27/59-3 & 27/59-4.

  • Page 48: Figure 1-49 Logic Diagram: Under/Over Voltage Elements (27/59)

    7SR11 & 7SR12 Description Of Operation Figure 1-49 Logic Diagram: Under/Over Voltage Elements (27/59) ©2012 Siemens Protection Devices Limited Chapter 1 Page 48 of 76...

  • Page 49: Voltage Protection: Negative Phase Sequence Overvoltage (47) - 7Sr12

    7SR11 & 7SR12 Description Of Operation 3.12 Voltage Protection: Negative Phase Sequence Overvoltage (47) – 7SR12 Negative phase sequence (NPS) voltage (V2) is a measure of the quantity of unbalanced voltage in the system. The relay derives the NPS voltage from the three input voltages (VL1, VL2 and VL3).

  • Page 50: 3.14 Voltage Protection: Under/Over Frequency (81) - 7Sr12

    7SR11 & 7SR12 Description Of Operation It should be noted that neutral voltage displacement can only be applied to VT arrangements that allow zero sequence flux to flow in the core i.e. a 5-limb VT or 3 single phase VTs. The VT primary winding neutral must be earthed to allow the flow of zero sequence current.

  • Page 51: Figure 1-52 Logic Diagram: Under/Over Frequency Detector (81)

    7SR11 & 7SR12 Description Of Operation Figure 1-52 Logic Diagram: Under/Over Frequency Detector (81) ©2012 Siemens Protection Devices Limited Chapter 1 Page 51 of 76...

  • Page 52: Section 4: Control & Logic Functions

    7SR11 & 7SR12 Description Of Operation Section 4: Control & Logic Functions Auto-Reclose (79) Optional Function 4.1.1 Overview A high proportion of faults on an Overhead Line (OHL) network are transient. These faults can be cleared and the network restored quickly by using Instantaneous (Fast) Protection trips followed by an automated sequence of Circuit Breaker reclosures after the line has been dead for a short time, this ‘deadtime’...

  • Page 53: Auto Reclose Sequences

    7SR11 & 7SR12 Description Of Operation Indications The Instruments Menu includes the following meters relevant to the status of the Auto-Reclose and Manual Closing of the circuit breaker: - Status of the AR sequence , AR Shot Count, CB Open Countdown Timer and CB Close Countdown...

  • Page 54: Autoreclose Prot'n Menu

    7SR11 & 7SR12 Description Of Operation The dead time is initiated when the trip output contact reset, the pickup is reset and the CB is open. The CB close output relay is energised after the dead time has elapsed. Figure 4-1 Typical AR Sequence with 3 Inst and 1 Delayed trip 4.1.3...
  • Page 55 7SR11 & 7SR12 Description Of Operation When set to Enabled the Relay will co-ordinate its sequence and shot count such that 79 Sequence Co-Ord it automatically keeps in step with downstream devices as they advance through their sequence. The Relay detects that a pickup has operated but has dropped-off before its...

  • Page 56: P/F Shots Sub-Menu

    7SR11 & 7SR12 Description Of Operation 4.1.5 P/F Shots sub-menu This menu allows the Phase fault trip/reclose sequence to be parameterized:- The first protection Trip in the P/F sequence can be set to either Inst or Delayed. 79 P/F Prot’n Trip1 Sets the first Reclose Delay (Dead time) in the P/F sequence.
  • Page 57 7SR11 & 7SR12 Description Of Operation 79 P/F Extern Trips to Lockout - Sets the number of allowed External protection’ trips, Relay will go to Lockout on the last Trip. These settings allow the user to set-up a separate AutoReclose sequence for external protection(s) having a different sequence to P/F, E/F or SEF protections.

  • Page 58: Figure 4-2 Basic Auto-Reclose Sequence Diagram

    7SR11 & 7SR12 Description Of Operation Figure 4-2 Basic Auto-Reclose Sequence Diagram ©2012 Siemens Protection Devices Limited Chapter 1 Page 58 of 76...

  • Page 59: Manual Cb Control

    7SR11 & 7SR12 Description Of Operation Manual CB Control A Manual Close Command can be initiated in one of three ways: via a Close CB binary input, via the data communication Channel(s) or from the relay CONTROL MODE menu. It causes an instantaneous operation via 79MC Close CB binary output, over-riding any DAR sequence in progress.

  • Page 60: Figure 4-3 Logic Diagram: Circuit Breaker Status

    7SR11 & 7SR12 Description Of Operation The ‘Reclaim time’ will start each time a Close Pulse has timed out and the CB has closed. Where a protection pickup is raised during the reclaim time the relay advances to the next part of the reclose sequence.
  • Page 61 7SR11 & 7SR12 Description Of Operation 79 Minimum LO Delay (Only in Auto-reclose models) Sets the time that the Relay’s Lockout condition is maintained. After the last allowed Trip operation in a specific sequence the Circuit Breaker will be left locked-out in the open position and can only be closed by manual or remote SCADA operation.

  • Page 62: Quick Logic

    7SR11 & 7SR12 Description Of Operation Quick Logic The ‘Quick Logic’ feature allows the user to input up to 4 logic equations (E1 to E4) in text format. Equations can be entered using Reydisp or at the relay fascia. Each logic equation is built up from text representing control characters. Each can be up to 20 characters long.

  • Page 63: Figure 4-4 Sequence Diagram: Quick Logic Pu/Do Timers (Counter Reset Mode Off)

    7SR11 & 7SR12 Description Of Operation Figure 4-4 Sequence Diagram: Quick Logic PU/DO Timers (Counter Reset Mode Off) When the count value = En Counter Target the output of the counter (En) = 1 and this value is held until the initiating conditions are removed when En is instantaneously reset.

  • Page 64: Section 5: Supervision Functions

    7SR11 & 7SR12 Description Of Operation Section 5: Supervision Functions Circuit Breaker Failure (50BF) The circuit breaker fail function has two time delayed outputs that can be used for combinations of re-tripping or back-tripping. CB Fail outputs are given after elapse of the 50BF-1 Delay or 50BF-2 Delay settings. The two timers run concurrently.

  • Page 65: Vt Supervision (60Vts) - 7Sr1205 & 7Sr1206

    7SR11 & 7SR12 Description Of Operation VT Supervision (60VTS) – 7SR1205 & 7SR1206 1 or 2 Phase Failure Detection Normally the presence of negative phase sequence (NPS) or zero phase sequence (ZPS) voltage in a power system is accompanied by NPS or ZPS current. The presence of either of these sequence voltages without the equivalent level of the appropriate sequence current is used to indicate a failure of one or two VT phases.

  • Page 66: Figure 4-6 Logic Diagram: Vt Supervision Function (60Vts)

    7SR11 & 7SR12 Description Of Operation Figure 4-6 Logic Diagram: VT Supervision Function (60VTS) ©2012 Siemens Protection Devices Limited Chapter 1 Page 66 of 76...

  • Page 67: Ct Supervision (60Cts)

    & Any 2 phases but not all 3 Figure 4-7 Logic Diagram: CT Supervision Function (60CTS) – 7SR11 This function is retained in the 7SR12 as it provides phase discrimination, whereas the standard function provided in the 7SR12 does not.

  • Page 68: Broken Conductor (46Bc)

    7SR11 & 7SR12 Description Of Operation Figure 4-8 Logic Diagram: CT Supervision Function (60CTS) – 7SR12 Broken Conductor (46BC) The element calculates the ratio of NPS to PPS currents. Where the NPS:PPS current ratio is above 46BC Setting an output is given after the 46BC Delay.

  • Page 69: Figure 4-11 Logic Diagram: Trip Circuit Supervision Feature (74Tcs)

    7SR11 & 7SR12 Description Of Operation The use of one or two binary inputs mapped to the same Trip Circuit Supervision element (e.g. 74TCS-n) allows the user to realise several alternative monitoring schemes. Figure 4-10 Logic Diagram: Trip Circuit Supervision Feature (74TCS) &...

  • Page 70: 2Nd Harmonic Block/Inrush Restraint (81Hbl2) Phase Elements Only

    7SR11 & 7SR12 Description Of Operation 2nd Harmonic Block/Inrush Restraint (81HBL2) phase elements only Inrush restraint detector elements are provided, these monitor the line currents. The inrush restraint detector can be used to block the operation of selected elements during transformer magnetising inrush conditions.

  • Page 71: Section 6: Other Features

    7SR11 & 7SR12 Description Of Operation Section 6: Other Features Data Communications Two communication ports, COM1 and COM2 are provided. RS485 connections are available on the terminal blocks at the rear of the relay (COM1). A USB port, (COM 2), is provided at the front of the relay for local access using a PC.

  • Page 72: Demand

    7SR11 & 7SR12 Description Of Operation auxiliary supply voltage. The data storage menu contains the settings for the Demand, Waveform and Fault storage features. 6.3.2 Demand Maximum, minimum and mean values of line currents, voltages and power (where applicable) are available as instruments which can be read in the relay INSTRUMENTS MENU or via Reydisp.

  • Page 73: Fault Records

    7SR11 & 7SR12 Description Of Operation Stored waveforms can be erased using the DATA STORAGE/Waveform Storage>Clear Waveforms setting or from Reydisp. 6.3.5 Fault Records Up to ten fault records can be stored and displayed on the Fascia LCD. Fault records can be triggered by user selected relay operations or via a suitably programmed binary input.

  • Page 74: Metering

    7SR11 & 7SR12 Description Of Operation When the accumulated Energy quantities reach a set increment, the Relay issues a pulse to the binary outputs: OUTPUT CONFIG/OUTPUT MATRIX> Active Exp Pulse, Active Imp Pulse, Reactive Exp Pulse and Reactive Imp Pulse.

  • Page 75: Operating Mode

    7SR11 & 7SR12 Description Of Operation Operating Mode The relay has three operating modes, Local, Remote and Out of Service. The following table identifies the functions operation in each mode. The modes can be selected by the following methods: SYSTEM CONFIG>OPERATING MODE setting, a Binary Input or Command...

  • Page 76: 2012 Siemens Protection Devices Limited Chapter

    The password validation screen also displays a numerical code. If the password is lost or forgotten, this code should be communicated to Siemens Protection Devices Ltd. and the password can be retrieved. ©2012 Siemens Protection Devices Limited Chapter 1 Page 76 of 76...

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