GE GEK 106168E manual Operating Theory, Magnetic Module, CPU Board

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5. HARDWARE DESCRIPTION

5.2. OPERATING THEORY

The DBF unit measures current signals, performs complex calculations using internal data, stores relevant incidents, pick-up tripping relays and generates information that can be used to determine the state of the associated electrical system. The DBF functionality is related to the following modules:

-Magnetic module

-CPU board

-Power supply

-Keyboard and display

5.2.1. MAGNETIC MODULE

The magnetic module performs two essential functions: galvanic insulation and scaling analog input signals. In the case of current transformers the input current for the primary winding is converted into a scaled voltage in the secondary winding. Each current transformer must be linear in the whole measurement range of the relay.

5.2.2. CPU BOARD

The DBF uses two 16-bit microprocessors operating at a clock frequency of 20 MHz. One of these microprocessors is used to perform the relay communications and the other performs the necessary calculations for protection functions. In general the microprocessors are responsible to perform the input and output calculations and operations at very high speed. The use of two microprocessors is especially recommendable to make the protection and communication functions independent of each other inside the unit itself, and therefore increase the reliability of the system.

The analogue-digital converter converts the voltage inputs into their digital equivalent with a resolution of 10 bits.

The unit code is stored in non-volatile EPROM memory while the settings and events are stored in EEPROM memory. The data related to the oscillography is stored in RAM memory which is maintained using a capacitor, thus avoiding the loss of information when the unit is disconnected.

A high-resolution real time clock is used to ensure that the date and time of all incidents can be time-tagged, with a resolution of one millisecond. This clock can be synchronized externally using an IRIG-B demodulated signal..

The input and output functions are divided between the two microprocessors. The serial ports, the keyboard and the display are controlled by the communications microprocessor. External communications are processed by a serial communications controller circuit which contains a universal asynchronous transceiver (DUART). The digital inputs and outputs are processed by the protection microprocessor.

The DBF contains 6 independent circuits to process digital inputs. These circuits check the presence or absence of input voltage and are designed to isolate them electrically from the microprocessor, thus increasing the reliability of the system.

On the front of the relay there is a set of 17 Target LED’s, one of which is fixed and indicates the operating state of the unit. The rest are user-configurable using GE_INTRO software.

The button situated on the front is designed to check the state of the Target LED’s and to reset them by keeping it pressed during 3 seconds.

GEK-106168E

DBF Breaker Failure Protection

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Contents GE Power Management 3KRQHHVFULSWLRQ0DQXDO*RI.\RXUFRGHTXHVWLRQ Ruvxjjhvwlrqd Page Table of Contents Installation and Maintenance List of Figures Rear View 226B7412 SheetDBF Breaker Failure Protection GEK-106168E ∙ Breaker internal arc detection Monitoring General DescriptionProtection AnalysisDBF Breaker Failure Protection GEK-106168E Overcurrent Units Digital Signal Input # TerminalsProtection Functions Low-Level Overcurrent Breaker Failure Unit 50BF 1PBreaker Failure without current or very low current Reset of Latching RelaysGround Overcurrent Breaker Failure Unit Breaker Arc Detection DeviceMeasurement Internal Protection Status SignalsMonitoring and Recording Functions Associated Breaker StatusGroup Status Comment Optional Exp. Board Closed Optional Exp. Board Latched#1Optional Exp.Boar Latched#2 Closed Internal Communication Status Signals LED Left Column Right Column Circuit Breaker Breaking Capacity MonitoringEvent Recorder Analysis FunctionsBUILT-IN SELF-CHECKING Unit OscillographyEvents to Trigger Oscillography Table Selection Active Table Tables of SettingsControl INPUT-1 INPUT-0Time Synchronization Configurable Inputs and OutputsFunction Outputs MAN-MACHINE Interface HMI Remote Communications Breaker Setting Group Active table setting groupInternal Arc Settings Common to all tables Range Default Step Oscillography MaskIndependent for each table Range Default Step 50BF Settings Functions PermittedComments on Settings DBF Breaker Failure Protection GEK-106168E DBF Ranges Models DBF PhaseModel List GroundMechanical Technical CharacteristicsElectrical Standards CommunicationsTest Standard Class DBF Breaker Failure Protection GEK-106168E Electrical Connections Physical DescriptionCase Internal ConstructionDBF Breaker Failure Protection GEK-106168E Magnetic Module Operating TheoryCPU Board Power Supply Keyboard and DisplayVisual Inspection Connections and Necessary EquipmentPanel Insulation Tests Indicators Relay SettingPower Supply Communications Digital Inputs InputsIRIG-B Synchronizing Input Functions 1 50BF 1P Unit Test2 50BF 3P Unit Test 4 3P no I Function Internal ARC TestNeutral Overcurrent Unit Test DBF Breaker Failure Protection GEK-106168E Current Measurement Relay Measurement TestsTiming Measurement DBF Breaker Failure Protection GEK-106168E Maintenance InstallationCONNECTION-TO-GROUND and Disturbances Suppression DBF Breaker Failure Protection GEK-106168E Keyboard and Display DBF General ElectricINF Menu TreeSET ACTModify Settings Protection Settings Group SET KEYView Settings Protection View Protection SettingsConfirm Setting OUT Range Level Valid RangeInformation Group INF KEY StatusControl Group ACT KEY SET DATE/TIMESingle KEY Menu Configuration Menu DBF Breaker Failure Protection GEK-106168E Figures Breaker Failure Logic 189C4114 Sheet External Connections 189C4114 Sheet Front View 226B7412 H9 Rear View 226B7412H10 Dimensions Diagram 226B6086H10 Panel Drilling 226B6086H10 RS232 Connection DBF Relay to PC
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