SEL 551 - User Manual

Date Code 20151105 Instruction Manual SEL-551 Relay List of Tables Table 1.1 Overcurrent Elements ............................................................................................................. 1.6 Table 2.1 Required Control Voltage Jumper Positions for Applied Nominal Control Voltage ...

Date Code 20151105 Instruction Manual SEL-551 Relay List of Figures Figure 1.1 SEL-551 Relays Applied Throughout the Power System ...................................................... 1.2 Figure 1.2 SEL-551 Inputs, Outputs, and Communications Port ......................................................

Date Code 20151105 Instruction Manual SEL-551 Relay Preface Manual Overview The SEL-551 Relay Instruction Manual describes common aspects of relay application and use. It includes the necessary information to install, set, test, and operate the relay and more detailed information about settings and ...

xii SEL-551 Relay Instruction Manual Date Code 20151105 Preface Safety Information Dangers, Warnings, and Cautions This manual uses three kinds of hazard statements, defined as follows: Safety Symbols The following symbols are often marked on SEL products. Safety Marks The following statements apply...

xiv SEL-551 Relay Instruction Manual Date Code 20151105 Preface General Information Typographic Conventions There are three ways to communicate with the SEL-551: ➤ Using a command line interface on a PC terminal emulation window. ➤ Using the front-panel menus and pushbuttons. ➤ Using AC SEL ERATOR Q...

Date Code 20151105 Instruction Manual SEL-551 Relay Section 1 Introduction and Specifications Overview The SEL-551 Overcurrent Relay and Reclosing Relay provides overcurrent protection and up to four shots of reclosing in one compact package. The relay measures phase and neutral currents—no voltages...

1.2 SEL-551 Relay Instruction Manual Date Code 20151105 Introduction and Specifications SEL-551 Model Changes ➤ Relay Word bit differences because of I/O mix and addition of programmable alarm conditions SALARM and HALARM. ➤ Latch Control Switches to Replace Traditional Latching Relays. ➤ Optional f...

1.3 Date Code 20151105 Instruction Manual SEL-551 Relay Introduction and Specifications Hardware Overview Hardware Overview ➤ Rear-panel: conventional terminal blocks or plug-in connectors (see Figure 2.7 and Figure 2.8) ➤ High-current interrupting output contacts: 10 A for L/R = 40 ms at 125 Vdc (i...

1.4 SEL-551 Relay Instruction Manual Date Code 20151105 Introduction and Specifications Specifications Specifications Sec tion 1 In trod uction a nd Spe cifica tion s Compliance Designed and manufactured under an ISO 9001 certified quality management system UL Listed to US and Canadian safety standa...

1.5 Date Code 20151105 Instruction Manual SEL-551 Relay Introduction and Specifications Specifications 48 Vdc: on for 38.4–60 Vdc; off below 28.8 Vdc 110 Vdc: on for 88–132 Vdc; off below 66 Vdc 125 Vdc: on for 105–150 Vdc; off below 75 Vdc 250 Vdc: on for 200–300 Vdc; off below 150 Vdc Frequency an...

1.6 SEL-551 Relay Instruction Manual Date Code 20151105 Introduction and Specifications Overcurrent Elements Section 1 In trod uction and Spe cifications Overcurrent Elements The OFF setting disables the overcurrent element. Time-Overcurrent Element Specifications See Section 4: Setting the Relay fo...

1.7 Date Code 20151105 Instruction Manual SEL-551 Relay Introduction and Specifications CT Saturation Protection Figure 1.4 SEL-551 Instantaneous Overcurrent Element Pickup Time Curve Figure 1.5 SEL-551 Relay Instantaneous Overcurrent Element Reset Time Curve CT Saturation Protection The SEL-551 pha...

1.8 SEL-551 Relay Instruction Manual Date Code 20151105 Introduction and Specifications Timer Specifications is significantly degraded. Combining the two filters provides an elegant solution for ensuring dependable phase instantaneous overcurrent element operation. Timer Specifications The SEL-551 h...

Date Code 20151105 Instruction Manual SEL-551 Relay Section 2 Installation Overview Design your installation using the mounting and connection information in this section. Options include rack or panel mounting and terminal block or plug-in connector (Connectorized ® ) wiring. This section also incl...

2.5 Date Code 20151105 Instruction Manual SEL-551 Relay Installation Rear-Panel Connections Figure 2.5 SEL-551 Front Panel, Rack-Mount Version (Half-Rack Width) Figure 2.6 SEL-551 Front Panel, Panel-Mount Version Rear-Panel Connections We provide two options for secure connection of wiring to the re...

2.6 SEL-551 Relay Instruction Manual Date Code 20151105 Installation Rear-Panel Connections and many industry applications have proven the performance of these connectors. In addition, we have tested these connectors thoroughly to ensure that they conform to our standards for protective relay applic...

2.7 Date Code 20151105 Instruction Manual SEL-551 Relay Installation Rear-Panel Connections Connectorized To use the Connectorized version of the SEL-551, ask your SEL sales or customer service representative for the appropriate Model Option Table and order wiring harness kit WA05510WxXyA, where x d...

2.15 Date Code 20151105 Instruction Manual SEL-551 Relay Installation Circuit Board Jumpers and Battery Circuit Board Jumpers and Battery Control Voltage Jumpers (SEL-551 With the Conventional Terminal Blocks Option) SEL-551 relays equipped with Conventional Terminal Blocks may be ordered with eithe...

2.17 Date Code 20151105 Instruction Manual SEL-551 Relay Installation Circuit Board Jumpers and Battery Output Contact OUT4 Control Jumper Refer to Figure 2.16 and Table 2.2. Main board jumper JMP13 controls the operation of output contact OUT4 . It provides the option of a second alarm output conta...

Date Code 20151105 Instruction Manual SEL-551 Relay Section 3 Relay Elements and Logic Relay Word Bits and SEL OGIC Control Equations This section describes relay elements and logic with numerous figures and accompanying text. Details on setting ranges are given in the setting sheets in Section 4: S...

3.2 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Relay Word Bits and SEL OGIC Control Equations In addition to Relay Word bits, numerals: 1 (logical 1) or 0 (logical 0) can be entered in a SEL OGIC control equations setting. If a SEL OGIC control equation setting is s...

3.4 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Optoisolated Inputs There are no optoisolated input settings such as: IN1 . = IN2 = Optoisolated inputs IN1 – IN2 receive their function by how their corresponding Relay Word bits IN1–IN2 are used in SEL OGIC control eq...

3.5 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Local Control Switches Local Control Switches Local control switches emulate traditional panel switches and are operated via the front-panel keyboard/display only (see Section 6: Front-Panel Interface; {CNTRL} pushbutto...

3.7 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Remote Control Switches Local Bit States Retained When Power Is Lost or Settings Changed Power Loss The states of the local bits (Relay Word bits LB1–LB8) are retained if power is lost to the relay and then it is restor...

3.8 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Instantaneous Overcurrent Elements The switch representation in this figure is derived from the standard: Graphics Symbols for Electrical and Electronics Diagrams IEEE Std 315-1975, CSA Z99-1975, ANSI Y32.2-1975, 4.11 C...

3.12 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Time-Overcurrent Elements Time-Overcurrent Elements See the setting sheets in Section 4: Setting the Relay for time-overcurrent element setting range information. See Trip Logic on page 3.17 for examples of tripping wi...

3.13 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Time-Overcurrent Elements The following is an example of 51P1T element operation; the other time-overcurrent elements operate similarly: Torque Control Setting SEL OGIC control equations setting 51P1TC (torque control ...

3.14 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Time-Overcurrent Elements Curve Timing/Reset Timing In addition to SEL OGIC control equations setting 51P1TC, phase time- overcurrent element 51P1T curve timing/reset timing are subject to settings: If reset timing set...

3.17 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Trip Logic Trip Logic The trip logic in Figure 3.13 provides flexible tripping with SEL OGIC control equation settings: Figure 3.13 Trip Logic Set Trip Any time setting TR = logical 1, Relay Word bit TRIP asserts to lo...

3.18 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Trip Logic Execution of the serial communications port OPEN command causes the TRIP Relay Word bit to assert to logical 1 if the TDURD timer is set greater than zero (0) cycles. Unlatch Trip Once Relay Word bit TRIP is...

3.19 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Trip Logic ➤ Local bit LB3 trips directly (operates as a manual trip switch via the front-panel). See Local Control Switches on page 3.5 and Section 6: Front-Panel Interface for more information on local control. With ...

3.20 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Close Logic Close Logic The close logic in Figure 3.14 provides flexible circuit breaker closing/auto reclosing with SEL OGIC control equation settings: Figure 3.14 Close Logic Set Close If all the following are true: ...

3.21 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Close Logic Unlatch Close If the CLOSE Relay Word bit is asserted at logical 1, it stays asserted at logical 1 until one of the following occurs: ➤ The unlatch close condition asserts (ULCL = logical 1), ➤ The circuit ...

3.22 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Reclosing Relay Defeat the Close Logic If SEL OGIC control equation setting 52A is set with numeral 0 (52A = 0), then the close logic is inoperable. Also, the reclosing relay is rendered nonexistent (see Reclosing Rela...

3.23 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Reclosing Relay The reclosing relay is in one and only one of these states (listed in Table 3.5) at any time. When in a given state, the corresponding Relay Word bit asserts to logical 1, and the LED illuminates. Autom...

3.25 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Reclosing Relay Reclosing Relay Timer Settings The open interval and reset timer factory settings are: The operation of these timers is affected by SEL OGIC control equation settings discussed later in this section. Al...

3.26 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Reclosing Relay Determination of Number of Reclosures (Last Shot) The number of reclosures (last shot) is equal to the number of open interval time settings that precede the first open interval time setting set equal t...

3.27 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Reclosing Relay When the shot counter is at a particular shot value (e.g., shot = 2), the corresponding Relay Word bit asserts to logical 1 (e.g., SH2 = logical 1). The shot counter also increments for sequence coordin...

3.28 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Reclosing Relay If the circuit breaker is open (IN1 = logical 0) when the TRIP Relay Word bit asserts (logical 0 to logical 1 transition), the relay goes to the Lockout State. This helps prevent reclose initiation for ...

3.32 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Reclosing Relay Additional Settings Example If the relay is used on a feeder with a cogenerator, it is desirable that the reclosing does not take place into a line energized by an islanded generator. A potential transf...

3.34 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Reclosing Relay Additional Settings Example 2 If the block reset timing setting is: 79BRS = 51P1 + 51G1 then reset timing is blocked if time-overcurrent pickup 51P1 or 51G1 is picked up, regardless of the reclosing rel...

3.38 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic SEL OGIC Control Equation Variables/Timers SEL OGIC Control Equation Variables/Timers Fourteen SEL OGIC Variables (SV1–SV14) are available. Ten of these SEL OGIC Variables have timer outputs, (SV5T–SV14T) (see Figure 3...

3.41 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Demand Ammetering Output Contacts OUT1 Through OUT4 Refer to Figure 3.23. The execution of the serial port command PULSE n (n = OUT1 – OUT4 ) asserts the corresponding Relay Word bit (OUT1–OUT4) to logical 1. The asser...

3.42 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Demand Ammetering The SEL-551 provides demand and peak demand ammetering for the following values: These demand and peak demand values are thermal demand values. Thermal demand ammetering is explained in the following ...

3.45 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Demand Ammetering Figure 3.27 Raise Pickup of Residual Ground Time-Overcurrent Element for Unbalance Current Residual Ground Demand Current Below Pickup GDEMP When unbalance current I G is low, unbalance demand current...

3.46 SEL-551 Relay Instruction Manual Date Code 20151105 Relay Elements and Logic Demand Ammetering Thus, the residual ground time-overcurrent element 51G1T operates with an effective, less-sensitive pickup: 50G1P = 2.30 A secondary The reduced sensitivity keeps the residual ground time-overcurrent ...

3.47 Date Code 20151105 Instruction Manual SEL-551 Relay Relay Elements and Logic Front-Panel Target LEDs Front-Panel Target LEDs Refer to Figure 2.5 for the arrangement of the target LEDs on the front panel of the SEL-551 relay. Further Target LED Details A, B, and C Target LEDs The following overc...

Date Code 20151105 Instruction Manual SEL-551 Relay Section 4 Setting the Relay Overview Change or view settings with the SET and SHOWSET serial port commands and the front-panel {SET} pushbutton. Table 4.1 lists the serial port SET commands. View settings with the respective serial port SHOWSET com...

4.13 Date Code 20151105 Instruction Manual SEL-551 Relay Setting the Relay Time-Overcurrent Element Setting Reference Information Figure 4.10 IEC Short-Time Inverse Curve: C5 10 20 30 40 50 60 70 80 90 100 1 2 3 4 5 6 7 8 9 .1 .2 .3 .4 .5 .6 .7 .8 .9 .01 .02 .03 .04 .05 .06 .07 .08 .09 100 1 2 3 4 5...

4.14 SEL-551 Relay Instruction Manual Date Code 20151105 Setting the Relay Relay Word Bit Setting Reference Information Relay Word Bit Setting Reference Information Relay Word bits are used in SEL OGIC control equation settings. See Section 3: Relay Elements and Logic for SEL OGIC control equations ...

4.18 SEL-551 Relay Instruction Manual Date Code 20151105 Setting the Relay Settings Explanations Settings Explanations Note that most of the settings in the settings sheets that follow include references for additional information. The following explanations are for relay settings (accessed under th...

4.19 Date Code 20151105 Instruction Manual SEL-551 Relay Setting the Relay Settings Explanations Example 1: Maximum Fault Current With an 80 A Instantaneous Setting Maximum fault current in terms of primary CT and ANSI voltage rating, burden in ohms, and X/R ratio is: Equation 4.2 Equation 4.2 is an...

4.20 SEL-551 Relay Instruction Manual Date Code 20151105 Setting the Relay Settings Sheets Equation 4.5 Example 3: Determine Whether the Following Application Meets the Above Criteria Apply Equation 4.1 to verify if the CTs meet the required criteria. Equation 4.6 The calculation shows that the 400:...

Date Code 20151105 Instruction Manual SEL-551 Relay Date _______________ SET.1 of 12 Settings Sheets for the SEL-551 Relay Relay Settings (SET Command) Settings Sheets for the SEL-551 Relay Relay Settings (SET Command) Identifier Labels (see Settings Explanations on page 4.18 ) Relay Identifier (12 ...

SET.2 of 12 Settings Sheets for the SEL-551 Relay Relay Settings (SET Command) SEL-551 Relay Instruction Manual Date Code 20151105 Date________________ Single-Phase Instantaneous Overcurrent Elements 50A, 50B, 50C (see Figure 3.5 ) Pickup (OFF, 0.5–80.0 A in 0.1 A increments) (5 A nominal)(OFF, 0.1–...

Date _______________ Date Code 20151105 Instruction Manual SEL-551 Relay SET.3 of 12 Settings Sheets for the SEL-551 Relay Relay Settings (SET Command) Curve (U1–U5, C1–C5; see Figure 4.1–Figure 4.10) 51N1C = Time Dial 0.50–15.00 for curves U1–U5 0.05–1.00 for curves C1–C5 51N1TD = Electromechanical...

SET.4 of 12 Settings Sheets for the SEL-551 Relay Relay Settings (SET Command) SEL-551 Relay Instruction Manual Date Code 20151105 Date________________ Negative-Sequence Time Overcurrent Element 51Q1T (see Figure 3.12 ) IMPORTANT: See Appendix F: Setting Negative-Sequence Overcurrent Elements for in...

Date _______________ Date Code 20151105 Instruction Manual SEL-551 Relay SET.5 of 12 Settings Sheets for the SEL-551 Relay Relay Settings (SET Command) Close Failure Timer (see Figure 3.14 ) Close Failure Time (0–54000 cycles in 0.125 cycle increments) CFD = Demand Ammetering Settings (see Figure 3....

SET.6 of 12 Settings Sheets for the SEL-551 Relay SEL OGIC Control Equation Settings (SET L Command) SEL-551 Relay Instruction Manual Date Code 20151105 Date________________ SV13 Pickup Time (0–54000.000 cycles in 0.125-cycle steps) SV13PU = SV13 Dropout Time (0–54000.000 cycles in 0.125-cycle steps...

Date _______________ Date Code 20151105 Instruction Manual SEL-551 Relay SET.7 of 12 Settings Sheets for the SEL-551 Relay SEL OGIC Control Equation Settings (SET L Command) Reclosing Relay (see Reclosing Relay on page 3.22 ) Reclose Initiate 79RI = Reclose Initiate Supervision 79RIS = Drive to Lock...

SET.8 of 12 Settings Sheets for the SEL-551 Relay Text Settings (SET T Command) SEL-551 Relay Instruction Manual Date Code 20151105 Date________________ Output Contacts (see Figure 3.23 ) Output Contact OUT1 OUT1 = Output Contact OUT2 OUT2 = Output Contact OUT3 OUT3 = Output Contact OUT4 OUT4 = Disp...

Date _______________ Date Code 20151105 Instruction Manual SEL-551 Relay SET.9 of 12 Settings Sheets for the SEL-551 Relay Text Settings (SET T Command) Local Bit LB4 Name (14 characters) NLB4 = Clear Local Bit LB4 Label (7 characters) CLB4 = Set Local Bit LB4 Label (7 characters) SLB4 = Pulse Local...

SET.10 of 12 Settings Sheets for the SEL-551 Relay Port Settings (SET P Command and Front Panel) SEL-551 Relay Instruction Manual Date Code 20151105 Date________________ Display if DP6 = logical 1 (16 characters) DP6_1 = Display if DP6 = logical 0 (16 characters) DP6_0 = Display if DP7 = logical 1 (...

Date _______________ Date Code 20151105 Instruction Manual SEL-551 Relay SET.11 of 12 Settings Sheets for the SEL-551 Relay Sequential Events Recorder Settings (SET R Command) Other Rear Port Settings Timeout (0–30 minutes) [PROTOCOL = SEL or LMD only] TIMEOUT = Send Auto Messages to Port (Y, N) [PR...

Date Code 20151105 Instruction Manual SEL-551 Relay Section 5 Serial Port Communications and Commands Overview The SEL-551 Relay is equipped with a serial communications port on the rear panel of the relay. Connect the serial port to a computer serial port for local communications or to a modem for ...

5.4 SEL-551 Relay Instruction Manual Date Code 20151105 Serial Port Communications and Commands Communications Protocol For long-distance communications up to 500 meters and for electrical isolation of communications ports, use the SEL-2800 or SEL-2810 Fiber-Optic Transceivers. Contact SEL for more ...

5.5 Date Code 20151105 Instruction Manual SEL-551 Relay Serial Port Communications and Commands Communications Protocol Based upon the port PROTOCOL setting, the relay activates either SEL ASCII, SEL LMD, or Modbus RTU protocol for the given port. SEL Fast Meter and SEL Compressed ASCII commands are...

5.6 SEL-551 Relay Instruction Manual Date Code 20151105 Serial Port Communications and Commands Communications Protocol The CAN character (ASCII hex 18) aborts a pending transmission. This is useful in terminating an unwanted transmission. Control characters can be sent from most keyboards with the ...

5.7 Date Code 20151105 Instruction Manual SEL-551 Relay Serial Port Communications and Commands Serial Port Automatic Messages Serial Port Automatic Messages When the serial port AUTO setting is Y, the relay sends automatic messages to indicate specific conditions. The automatic messages are describ...

5.8 SEL-551 Relay Instruction Manual Date Code 20151105 Serial Port Communications and Commands Serial Port Access Levels Serial Port Access Levels Commands can be issued to the relay via the serial port to view metering values, change relay settings, etc. The available serial port commands are list...

5.9 Date Code 20151105 Instruction Manual SEL-551 Relay Serial Port Communications and Commands Command Summary Commands CLO through SET in Table 5.4 can be executed from Access Level 2. For example, enter the SET command at the Access Level 2 prompt to make relay settings: =>> SET <Enter&g...

5.11 Date Code 20151105 Instruction Manual SEL-551 Relay Serial Port Communications and Commands Command Explanations The serial port command explanations that follow in Command Explanations on page 5.11 are in the same order as the commands listed in Table 5.4. Command Explanations Access Level 0 C...

5.19 Date Code 20151105 Instruction Manual SEL-551 Relay Serial Port Communications and Commands Command Explanations After the STA command is entered, the relay replies with the following status report: FEEDER 1 Date: 03/05/96 Time: 14:17:01.359STATION A FID=SEL-551-R100-Vr-D960226 CID=00FF SELF TE...

5.25 Date Code 20151105 Instruction Manual SEL-551 Relay Serial Port Communications and Commands Command Explanations To pulse OUT1 for five seconds: =>> PUL OUT1 5 <Enter> Are you sure (Y/N) ? Y <Enter> =>> If the response to the Are you sure (Y/N) ? prompt is N or n , the c...

Date Code 20151105 Instruction Manual SEL-551 Relay SEL-551 Command Summary Access Level 0 Command The only thing that can be done at Access level 0 is to go to Access Level 1. The screen prompt is: = ACC Enters Access Level 1. If the main board password jumper is not in place, the relay prompts for...

Date Code 20151105 Instruction Manual SEL-551 Relay Section 6 Front-Panel Interface Overview This section describes how to get information, make settings, and execute control operations from the relay front panel. It also describes the default displays. Front-Panel Pushbutton Operation Overview Note...

6.2 SEL-551 Relay Instruction Manual Date Code 20151105 Front-Panel Interface Front-Panel Pushbutton Operation the metering values available via the front-panel {METER} pushbutton, refer to the MET Command (Meter) on page 5.14) and MET D Command (Demand Ammeter) on page 5.15. A few of the front-pane...

6.3 Date Code 20151105 Instruction Manual SEL-551 Relay Front-Panel Interface Front-Panel Pushbutton Operation q Front-panel pushbutton functions that correspond to Access Level 1 serial port commands do not require the entry of the Access Level 1 password through the front panel. w Front-panel push...

6.4 SEL-551 Relay Instruction Manual Date Code 20151105 Front-Panel Interface Functions Unique to the Front-Panel Interface Figure 6.4 SEL-551 Front-Panel Pushbuttons-Secondary Functions Functions Unique to the Front-Panel Interface Two front-panel primary functions do not have serial port command e...

6.7 Date Code 20151105 Instruction Manual SEL-551 Relay Front-Panel Interface Functions Unique to the Front-Panel Interface If the breaker is closed, the reclosing relay reset timer times out (79RSLD = 300), the relay goes to the reset state (front-panel LO LED extinguishes and RS LED illuminates), ...

6.8 SEL-551 Relay Instruction Manual Date Code 20151105 Front-Panel Interface Functions Unique to the Front-Panel Interface View Local Control Access local control via the {CNTRL} pushbutton. If local control switches exist (i.e., corresponding switch position label settings were made), the followin...

6.9 Date Code 20151105 Instruction Manual SEL-551 Relay Front-Panel Interface Functions Unique to the Front-Panel Interface Operate Local Control (With Factory Settings) Press the right arrow pushbutton, and scroll back to the first set local control switch in the factory default settings: Press the...

6.10 SEL-551 Relay Instruction Manual Date Code 20151105 Front-Panel Interface Functions Unique to the Front-Panel Interface Because this is an OFF/MOMENTARY type switch, the MANUAL TRIP switch returns to the RETURN position after momentarily being in the TRIP position. Technically, the MANUAL TRIP ...

6.11 Date Code 20151105 Instruction Manual SEL-551 Relay Front-Panel Interface Rotating Default Display Rotating Default Display The relay name, SEL-551 , displays if no local control is operational (i.e., no corresponding switch position label settings were made) and no display point labels are ena...

Date Code 20151105 Instruction Manual SEL-551 Relay Section 7 Standard Event Reports and SER Overview The SEL-551 Relay has two styles of event reports: ➤ Standard 15-cycle event reports ➤ Sequential events recorder (SER) event report These event reports contain date, time, current, relay element, o...

7.2 SEL-551 Relay Instruction Manual Date Code 20151105 Standard Event Reports and SER Standard 15-Cycle Event Reports Relay Word Bit TRIP Relay Word bit TRIP would usually be assigned to an output contact for tripping a circuit breaker (e.g., SEL OGIC control equations setting OUT1 = TRIP). SEL OGI...

7.3 Date Code 20151105 Instruction Manual SEL-551 Relay Standard Event Reports and SER Standard 15-Cycle Event Reports See Section 5: Serial Port Communications and Commands for more information on serial port commands. Standard Event Report Summary Each time the relay generates a standard 15-cycle ...

7.5 Date Code 20151105 Instruction Manual SEL-551 Relay Standard Event Reports and SER Standard 15-Cycle Event Reports The EVENT serial port commands can be entered with only the first three letters of the word EVENT. For example, the second most recent 1/8-cycle resolution event report can be retri...

7.8 SEL-551 Relay Instruction Manual Date Code 20151105 Standard Event Reports and SER Sequential Events Recorder (SER) Event Report Sequential Events Recorder (SER) Event Report See Figure 7.5 for an example SER event report. SER Event Report Row Triggering The relay triggers (generates) a row in t...

7.11 Date Code 20151105 Instruction Manual SEL-551 Relay Standard Event Reports and SER Example Standard 15-Cycle Event Report If Y is entered, the relay clears the SER event reports from nonvolatile memory. If N is entered, no reports are cleared, and the relay responds: Canceled SER Event Report C...

Date Code 20151105 Instruction Manual SEL-551 Relay Section 8 Testing and Troubleshooting Overview The Acceptance Testing on page 8.4, Commissioning Testing on page 8.14, and Maintenance Testing on page 8.15 should be used for determining and establishing test routines for the SEL-551 Relay. Include...

8.2 SEL-551 Relay Instruction Manual Date Code 20151105 Testing and Troubleshooting Testing Methods and Tools For more information on these features and commands, see Section 5: Serial Port Communications and Commands. Low-Level Test Interface The SEL-551 has a low-level test interface between the c...

8.3 Date Code 20151105 Instruction Manual SEL-551 Relay Testing and Troubleshooting Testing Methods and Tools Step 3. Monitor element pickup and dropout by observing the target LEDs. For example, the level 1 phase instantaneous overcurrent element 50P1 appears in Relay Word Row 2. When you type the ...

8.4 SEL-551 Relay Instruction Manual Date Code 20151105 Testing and Troubleshooting Acceptance Testing Acceptance Testing When: Qualifying a relay model to be used on the utility system. Goal: ➤ Ensure relay meets published critical performance specifications such as operating speed and element accu...

8.5 Date Code 20151105 Instruction Manual SEL-551 Relay Testing and Troubleshooting Acceptance Testing Figure 8.2 Relay Part Number and Hardware Identification Sticker Power Supply Step 1. Purpose: Establish control power connections. Method: Connect a frame ground to terminal marked GND on the rear...

8.7 Date Code 20151105 Instruction Manual SEL-551 Relay Testing and Troubleshooting Acceptance Testing =>> SHO <Enter> Relay Settings:RID =FEEDER 1 TID =STATION ACTR = 120 CTRN = 120 TDURD = 9.00050P1P = 15.0 50P2P = 20.0 50P3P = OFF 50P4P = OFF50P5P = OFF 50P6P = OFF 50ABCP= OFF51P1P = ...

8.8 SEL-551 Relay Instruction Manual Date Code 20151105 Testing and Troubleshooting Acceptance Testing b. Apply the appropriate control voltage to each input and make sure the corresponding target LED turns on. Note that the control voltage required to assert an input is jumper selectable. If you su...

8.14 SEL-551 Relay Instruction Manual Date Code 20151105 Testing and Troubleshooting Commissioning Testing Residual Ground Overcurrent Elements The SEL-551 has four residual ground overcurrent elements. They all operate based on a comparison between a residual calculation of the three-phase inputs a...

8.15 Date Code 20151105 Instruction Manual SEL-551 Relay Testing and Troubleshooting Maintenance Testing Maintenance Testing When: At regularly scheduled intervals, or when there is an indication of a problem with the relay or system. Goals: ➤ Ensure that the relay is measuring ac quantities accurat...

8.17 Date Code 20151105 Instruction Manual SEL-551 Relay Testing and Troubleshooting Relay Troubleshooting Relay Troubleshooting Inspection Procedure Complete the following procedure before disturbing the relay. After you finish the inspection, proceed to the Troubleshooting Procedure. Step 1. Measu...

8.18 SEL-551 Relay Instruction Manual Date Code 20151105 Testing and Troubleshooting Relay Calibration Relay Calibration The SEL-551 is factory-calibrated. If you suspect that the relay is out of calibration, please contact the factory. Factory Assistance We appreciate your interest in SEL products ...

Date Code 20151105 Instruction Manual SEL-551 Relay Appendix A Firmware and Manual Versions Firmware Determining the Firmware Version in Your Relay To find the firmware revision number in your relay, view the status report using the serial port STATUS command or the front-panel {STATUS} pushbutton. ...

Date Code 20151105 Instruction Manual SEL-551 Relay Appendix B Firmware Upgrade Instructions The SEL-551 Relay includes two firmware configurations: ➤ EPROM ➤ Flash Upgrade EPROM firmware by replacing an integrated circuit (IC) component on the SEL-551 main board. Upgrade Flash firmware by downloadi...

B.2 SEL-551 Relay Instruction Manual Date Code 20151105 Firmware Upgrade Instructions EPROM Firmware Upgrades Required Equipment ➤ Phillips ® screwdriver ➤ Personal computer ➤ Terminal emulation software ➤ Serial communications cable (SEL-234A or equivalent) ➤ ESD workstation (grounding pad and wris...

B.5 Date Code 20151105 Instruction Manual SEL-551 Relay Firmware Upgrade Instructions Flash Firmware Upgrades Step 19. After this procedure is completed and changes have been saved, execute the QUIT command. The relay is now ready for your commissioning procedure. Flash Firmware Upgrades Required Eq...

Date Code 20151105 Instruction Manual SEL-551 Relay Appendix C SEL Distributed Port Switch Protocol Overview SEL Distributed Port Switch Protocol (LMD) permits multiple SEL relays to share a common communications channel. It is appropriate for low-cost, low-speed port switching applications where up...

Date Code 20151105 Instruction Manual SEL-551 Relay Appendix D Configuration, Fast Meter, and Fast Operate Commands Overview SEL relays have two separate data streams that share the same serial port. The human data communications with the relay consist of ASCII character commands and reports that ar...

D.2 SEL-551 Relay Instruction Manual Date Code 20151105 Configuration, Fast Meter, and Fast Operate Commands Message Definitions Message Definitions A5C0 Relay Definition Block In response to the A5C0 request, the relay sends the following block: A5C1 Fast Meter Configuration Block In response to th...

D.8 SEL-551 Relay Instruction Manual Date Code 20151105 Configuration, Fast Meter, and Fast Operate Commands Message Definitions ID Message In response to the ID command, the relay sends the following: <STX>"FID STRING ENCLOSED IN QUOTES","yyyy" <CR>"BFID STRING ENCLO...

Date Code 20151105 Instruction Manual SEL-551 Relay Appendix E Compressed ASCII Commands Overview The SEL-551 Relay provides Compressed ASCII versions of some relay ASCII commands. The Compressed ASCII commands allow an external device to obtain data from the relay, in a format which directly import...

E.3 Date Code 20151105 Instruction Manual SEL-551 Relay Compressed ASCII Commands CASCII Command—SEL-551 CASCII Command—SEL-551 Display the SEL-551 Compressed ASCII configuration message by sending: CAS <CR> The SEL-551 sends: <STX>"CAS",5,"01A8"<CR>"CST",1,...

E.4 SEL-551 Relay Instruction Manual Date Code 20151105 Compressed ASCII Commands CHISTORY Command—SEL-551 CHISTORY Command—SEL-551 Display history data in Compressed ASCII format by sending: CHI <CR> The SEL-551 sends: <STX>"REC_NUM","MONTH","DAY","YEAR",...

Date Code 20151105 Instruction Manual SEL-551 Relay Appendix F Setting Negative-Sequence Overcurrent Elements Setting Negative-Sequence Definite-Time Overcurrent Elements Negative-sequence instantaneous overcurrent elements 50Q1 and 50Q2 should not be set to trip directly. This is because negative-s...

F.3 Date Code 20151105 Instruction Manual SEL-551 Relay Setting Negative-Sequence Overcurrent Elements Coordinating Negative-Sequence Overcurrent Elements feeder relay in this example. Note that the overcurrent element labels in the example are not the same as the labels of the corresponding SEL-551...

F.4 SEL-551 Relay Instruction Manual Date Code 20151105 Setting Negative-Sequence Overcurrent Elements Coordinating Negative-Sequence Overcurrent Elements I F = Maximum load current through feeder relay = 450 A I R = Maximum load current through line recloser = 150 A 51F = Feeder relay phase time-ov...

F.5 Date Code 20151105 Instruction Manual SEL-551 Relay Setting Negative-Sequence Overcurrent Elements Coordinating Negative-Sequence Overcurrent Elements Figure F.4 Phase-to-Phase Fault Coordination 51EP: pickup = 300 A (below max. feeder load, I F ) Considerable improvement in sensitivity and spee...

Date Code 20151105 Instruction Manual SEL-551 Relay Appendix G Modbus RTU Communications Protocol Overview This appendix describes Modbus ® RTU communications features supported by the SEL-551 Relay. Complete specifications for the Modbus protocol are available from the Modicon website at www.modico...

G.2 SEL-551 Relay Instruction Manual Date Code 20151105 Modbus RTU Communications Protocol Modbus RTU Communications Protocol The cyclical redundancy check detects errors in the received data. If an error is detected, the relay discards the packet. Modbus Responses The slave device sends a response ...

G.12 SEL-551 Relay Instruction Manual Date Code 20151105 Modbus RTU Communications Protocol Modbus RTU Communications Protocol Remote Bits Command Code 0Ch-Control Remote Bits: This code controls the remote bits. This command code has two parameters. Parameter 1 determines the bit operation. Paramet...

G.28 SEL-551 Relay Instruction Manual Date Code 20151105 Modbus RTU Communications Protocol Modbus RTU Communications Protocol NOTE 4: The Modbus map (Table G.18) provides a feature that allows you to download complete event data via Modbus. See Table G.17 for data descriptions. NOTE 5: Please refer...