cycle time and frequency tracking
DESCRIPTION
frequency tracking and cycle time presentationTRANSCRIPT
Cycle Time and Frequency TrackingIntroduction
Praveen.A.N, Sr. Engineer, PG – GAS – 05/05/2016
Objective
§ Recognize and Understand
§ Task time groups
§ Cycle – Time of a function block
§ Order of a function block
§ Understand SMAI configuration
§ Parameters of SMAI configuration
§ Frequency Tracking
§ Case study
§ Consequence of wrong execution order and cycle time
§ Consequence of wrong frequency tracking setting
Month DD, Year | Slide 2© ABB Group
Cycle Time and Execution Order
§ Execution of functions in ACT runs according to a fixedsequencey with different cycle time
§ For each cycle time, function block has a serial execitionnumber.
§ Classified as fast, medium and slow
§ Time value different between 650 and 670 series.
Application ManualREG670
Task Time Group
Month DD, Year | Slide 3© ABB Group
Cycle Time and Execution OrderLogical Function Blocks (FB) in IEDs
Month DD, Year | Slide 4© ABB Group
Cycle Time and Execution Order
§ Execution of different function blocks within the same cycleis determined by the serial execution number.
§ Additional time delays might be needed when connectingFB with fast cycle time to FB with slow cycle time
Month DD, Year | Slide 5© ABB Group
Cycle Time and Execution Order
Technical ReferenceManual – REG670
Month DD, Year | Slide 6© ABB Group
SMAI
§ Used to process the analog signals
§ All information of the analog signal like the RMS value,phase angle, frequency, harmonic content, sequencecomponent etc (about 244 values in total)
§ Information from the SMAI is then used in different functionblock in ACT.
Pre-processor Function Block
Month DD, Year | Slide 7© ABB Group
Technical ReferenceManual – REG670
SMAITask Time Groups
Month DD, Year | Slide 8© ABB Group
Frequency Tracking
§ Adaptive frequency tracking is needed in order to ensureproper operation of DFT based functions during varyingfrequency conditions.
§ Frequency tracking is set using the DFTRefExtOut andDFTReference settings.
§ These parameters provide DFT reference for DFTcalculations.
§ InternalDFTRef uses fixed DFT reference based on setsystem frequency.
§ ExternalDFTRef will use reference based on inputDFTSPFC.
Parameter and Principle
Month DD, Year | Slide 9© ABB Group
Frequency Tracking
§ Selected reference instance of SMAI must be voltage type.
§ Positive sequence voltage is used for the frequencytracking feature.
§ IntBlockLevel is set in % of Ubase / √3.
§ If the positive sequence voltage is lower thanIntBlockLevel, the feature is blocked.
§ Adaptive frequency tracking is applicable for IEDs ingenerating stations during start – up and shut – down.
Parameter and Principle
Month DD, Year | Slide 10© ABB Group
Frequency Tracking
§ Generator Differential Protection
§ Transformer Differential protection
§ Over – Current and Earth Fault Protection
§ Residual Over – Voltage and Over and under VoltageProtection
§ Over – Excitation Protection
§ Measurement Function
Examples of DFT Based Function
Month DD, Year | Slide 11© ABB Group
Frequency TrackingSMAI
Month DD, Year | Slide 12© ABB Group
Frequency TrackingSMAI
Month DD, Year | Slide 13© ABB Group
Frequency TrackingSMAI
Month DD, Year | Slide 14© ABB Group
