Siemens siprotec 7SD5 User Manual

2.18 Frequency Protection (optional)
345
7SD5 Manual
C53000-G1176-C169-1
The following 3 options are available:
•Stage OFF: The stage is ineffective;
•Stage ON: with Trip: The stage is effective and issues an alarm and a trip
command (after time has expired) following irregular frequency deviations;
•Stage ON: Alarm only: The stage is effective and issues an alarm but no trip
command following irregular frequency deviations.
Pickup Values,
Delay Time
The configured pickup value determines whether a frequency element is to respond
to overfrequency or underfrequency.
• If a stage is set to a value above
the rated frequency, it is automatically interpreted
to be an overfrequency
stage f>.
• If a stage is set to a value below
the rated frequency, it is automatically interpreted
to be an underfrequency
stage f<.
• If a stage is set exactly to the rated frequency
, it is inactive.
A pickup value can be set for each stage according to above rules. The addresses and
possible setting ranges are determined by the nominal frequency as configured in the
Power System Data 1 (Section 2.1.2.1) in Rated Frequency (address 230).
Please note that none of the frequency stages is set to less than 30 mHz above (for
f>) or below (for f<) of the nominal frequency. Since the frequency stages have a hys-
teresis of approx. 20 mHz, it may otherwise happen that the element does not drop
out when returning to the nominal frequency.
Only those addresses are accessible that match the configured nominal frequency.
For each element, a trip delay time can be set:
•Address 3602 f1 PICKUP pickup value for frequency stage f1 at f
N
= 50 Hz,
Address 3603 f1 PICKUP pickup value for frequency stage f1 at f
N
= 60 Hz,
Address 3604 T f1 trip delay for frequency stage f1;
•Address 3612 f2 PICKUP pickup value for frequency stage f2 at f
N
= 50 Hz,
Address 3613 f2 PICKUP pickup value for frequency stage f2 at f
N
= 60 Hz,
Address 3614 T f2 trip delay for frequency element f2;
•Address 3622 f3 PICKUP pickup value for frequency stage f3 at f
N
= 50 Hz,
Address 3623 f3 PICKUP pickup value for frequency stage f3 at f
N
= 60 Hz,
Address 3624 T f3 trip delay for frequency stage f3;
•Address 3632 f4 PICKUP pickup value for frequency stage f4 at f
N
= 50 Hz,
Address 3633 f4 PICKUP pickup value for frequency stage f4 at f
N
= 60 Hz,
Address 3634 T f4 trip delay for frequency element f4.
The set times are additional delay times not including the operating times (measuring
time, dropout time) of the protective function.
If underfrequency protection is used for load shedding purposes, then the frequency
settings relative to other feeder relays are generally based on the priority of the cus-
tomers served by the protective relay. Normally, it is required for load shedding a fre-
cuency / time grading that takes into account the importance of the consumers or con-
sumer groups.
In interconnected networks, frequency deviations may also be caused by power
swings. Depending on the power swing frequency, the mounting location of the device
and the setting of the frequency stages, it is reasonable to block the entire frequency
protection function or single stages once a power swing has been detected. The delay
times must then be co-ordinated thus that a power swing is detected before the fre-
quency protection trips.
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Siemens siprotec 7SD5 Specifications

General

Rated Frequency	50/60 Hz
Current Input	1 A / 5 A
Display	LCD
Voltage Supply	24-250 V DC / 100-240 V AC
Communication Interfaces	Ethernet, RS485, USB
Protocols	IEC 61850, DNP3, Modbus
Protection Functions	Overcurrent, Distance
Mounting	Panel mounting
Operating Temperature	-25°C to +70°C

Summary

Preface

Purpose of this Manual

Describes the content and structure of the manual for the 7SD5 device.

Target Audience

Identifies the intended readers for this manual, including engineers and technicians.

Instructions and Warnings

Explains the meaning of DANGER, WARNING, CAUTION, and NOTE indicators used in the manual for safety.

QUALIFIED PERSONNEL

Defines the prerequisites and qualifications required for personnel working with the device.

Typographic and Graphical Conventions

Explains the use of fonts, symbols, and graphical conventions within the manual.

Introduction

Overall Operation

Describes the device's microcomputer system, analog inputs, and basic structure.

Application Scope

Details the device's capabilities in protecting overhead lines and cables with multi-end infeeds.

Characteristics

Outlines general features and specific characteristics of differential and distance protection functions.

Functions

General

Provides general information on device settings, system data, and interaction with protection functions.

Differential Protection

Explains the principle of differential protection, including its application for lines and busbars.

Distance Protection

Details the distance protection function, including fault detection, impedance calculation, and characteristics.

Automatic Reclosure Function (optional)

Describes the automatic reclosure functionality, its operation, and configuration.

Monitoring Functions

Covers hardware and software monitoring, including measurement supervision and malfunction responses.

Function Control and Circuit Breaker Test

Explains device control, circuit breaker position detection, and testing procedures.

Ancillary Functions

Details additional functions such as commissioning tools, message processing, and fault record storage.

Mounting and Commissioning

Mounting and Connections

Provides guidance on device installation, including prerequisites and connection examples for current and voltage transformers.

Checking Connections

Details procedures for checking serial interfaces, protection data communication, and system interfaces.

Commissioning

Covers essential commissioning steps, including test modes, time synchronization, and system interface checks.

Final Preparation of the Device

Describes final checks and settings required before the device is ready for operation.

Technical Data

General

Presents general technical specifications for current inputs, auxiliary voltage, and binary inputs/outputs.

Differential Protection

Lists technical data for differential protection, including pickup values and tripping times.

Distance Protection (optional)

Provides technical data for distance protection, covering earth impedance, phase preferences, and fault detection.

Automatic Reclosure Function (optional)

Details technical data for automatic reclosure, including number of reclosures, control modes, and adaptive dead times.

Synchronism and Voltage Check (optional)

Provides technical data for synchronism and voltage check functions, including operating modes and voltage thresholds.

Undervoltage and Overvoltage Protection (optional)

Lists technical data for undervoltage and overvoltage protection stages for phase, sequence systems.

Frequency Protection (optional)

Presents technical data for frequency protection, including stages, pickup values, and operating ranges.

Fault Locator

Provides technical data for the fault locator function, including start modes and output options.

Circuit Breaker Failure Protection

Details technical data for circuit breaker failure protection, including current flow monitoring and delay times.

Thermal Overload Protection

Lists technical data for thermal overload protection, including setting ranges and tripping characteristics.

Monitoring Function

Provides technical data for monitoring functions, covering hardware, software, and measurement circuit checks.

User Defined Functions (CFC)

Lists technical data for user-defined functions, including function modules and task level assignments.

Dimensions

Provides mechanical dimensions for panel flush, cubicle, and surface mounting.

Appendix

Ordering Information and Accessories

Contains information for ordering devices and accessories, including order codes and descriptions.

Terminal Assignments

Details terminal assignments for panel flush, cubicle, and surface mounting for various device types.

Connection Examples

Provides connection examples for current transformers, voltage transformers, and pilot wires.

Default Settings

Lists default settings for LEDs, binary inputs, binary outputs, and function keys.

Functional Scope

Details the functional scope of the device, including protection and ancillary functions.

Settings

Provides a comprehensive table of all configurable parameters, their setting options, and default values.

Information List

Lists all device information, including status signals, fault indications, and measurement values.