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24/30496142 DC BS EN IEC 61869-7 Instrument transformers - Part 7. Specific requirements for electronic Voltage Transformers, 2024
- 38_793e_CD.pdf [Go to Page]
- FOREWORD
- INTRODUCTION
- 1 Scope
- 2 Normative reference
- 3 Terms, definitions, symbols and abbreviated terms [Go to Page]
- 3.1 Terms and definitions
- 3.2 Index of abbreviations
- 4 Normal and special environmental conditions [Go to Page]
- 4.1 General
- 4.2 Normal environmental conditions [Go to Page]
- 4.2.1 Ambient air temperature
- 4.2.2 Altitude
- 4.2.3 Vibrations or earth tremors
- 4.2.4 Exposure to pollution
- 4.2.5 Other environmental conditions for indoor instrument transformers
- 4.2.6 Other environmental conditions for outdoor instrument transformers
- 4.2.7 IT with outdoor parts
- 4.3 Special environmental conditions [Go to Page]
- 4.3.1 General
- 4.3.2 Altitude
- 4.3.2.1 Influence of altitude on external insulation
- 4.3.2.2 Influence of altitude on temperature rise
- 4.3.3 Ambient temperature
- 4.3.4 Vibrations or earth tremors
- 4.3.5 Earthquakes
- 5 Ratings [Go to Page]
- 5.1 General
- 5.2 Voltage ratings [Go to Page]
- 5.2.1 Highest voltage for equipment (Um)
- 5.2.2 Power system earthing
- 5.2.3 Standard values for rated primary voltage (Upr)
- 5.2.4 Standard values for rated secondary voltage (Usr)
- 5.2.5 Rated auxiliary power supply voltage (Uar)
- 5.2.5.1 General
- 5.2.5.2 Rated AC auxiliary voltage
- 5.2.5.3 Rated DC auxiliary voltage
- 5.2.5.4 Insulation requirements for power supply terminals
- 5.3 Current Ratings [Go to Page]
- 5.3.1 Standard values for rated primary current (Ipr)
- 5.3.2 Standard values of rated secondary current (Isr)
- 5.3.3 Standard value of rated continuous thermal current (Icth)
- 5.3.4 Short time current ratings
- 5.3.4.1 Rated short-time thermal current (Ith)
- 5.3.4.2 Rated dynamic current (Idyn)
- 5.3.4.3 Rated internal arc fault current (Iarc)
- 5.4 Dielectric ratings [Go to Page]
- 5.4.1 General
- 5.4.2 Rated primary terminal insulation level
- 5.4.3 Other requirements for primary terminal insulation
- 5.4.3.1 Partial discharges
- 5.4.3.2 Chopped lightning impulse
- 5.4.3.3 Capacitance and dielectric dissipation factor (tanδ)
- 5.4.4 Between-section insulation requirements
- 5.4.5 Insulation requirements for secondary terminals and low-voltage components
- 5.4.5.1 General requirements
- 5.4.5.2 Special requirements for LPITs
- 5.4.5.3 DC insulation resistance requirement
- 5.5 Rated frequency (fr)
- 5.6 Output ratings [Go to Page]
- 5.6.1 Rated output for inductive instrument transformers and CVTs
- 5.6.2 Rated burden for LPITs
- 5.6.3 Standard values for the rated delay time for EITs (tdr)
- 5.7 Accuracy requirements [Go to Page]
- 5.7.1 General
- 1.1.1 Accuracy based on corrected transformation
- 5.7.2 Rated accuracy class
- 5.7.3 Accuracy class extension for harmonics
- 5.7.4 Accuracy requirements for harmonics
- 5.7.5 Harmonic requirements for LPIT protection accuracy classes
- 5.7.6 Anti-aliasing filter for EIT using digital data processing
- 5.7.701 Measuring LPVT
- 5.7.701.1 Accuracy class designation
- 5.7.701.2 Standard accuracy classes
- 5.7.701.3 Limits of ratio error (ε) and phase error (() for measuring LPVT at rated frequency
- 5.7.702 Protective LPVT
- 5.7.702.1 Accuracy class designation
- 5.7.702.2 Standard accuracy classes
- 5.7.702.3 Limits of ratio error, phase error for protective and multipurpose LPVT
- 5.7.704 Limits for the secondary voltage offset and noise
- 6 Design and construction [Go to Page]
- 6.1 Requirements for liquids used in equipment [Go to Page]
- 6.1.1 General
- 6.1.2 Liquid quality
- 6.1.3 Liquid level indicator
- 6.1.4 Liquid tightness
- 6.2 Requirements for gases used in equipment [Go to Page]
- 6.2.1 General
- 6.2.2 Gas quality
- 6.2.3 Gas monitoring device
- 6.2.4 Gas tightness
- 6.2.4.1 General
- 6.2.4.2 Closed pressure systems for gas
- 6.2.4.3 Pressure-relief device
- 6.3 Requirements for solid materials used in equipment
- 6.4 Requirements for temperature rise of parts and components [Go to Page]
- 6.4.1 General
- 6.4.2 Influence of altitude on temperature rise
- 6.5 Requirements for earthing of equipment [Go to Page]
- 6.5.1 General
- 6.5.2 Earthing of the enclosure [Go to Page]
- 6.5.2.1 GIS enclosure
- 6.5.2.2 Enclosure of low-voltage components
- 6.5.3 Electrical continuity
- 6.6 Requirements for the external insulation [Go to Page]
- 6.6.1 Pollution
- 6.6.2 Altitude
- 6.7 Mechanical requirements
- 6.8 Multiple chopped impulses on primary terminals
- 6.9 Internal arc fault protection requirements
- 6.10 Degrees of protection by enclosures [Go to Page]
- 6.10.1 General
- 6.10.2 Protection against access to hazardous parts and protection of the equipment against ingress of solid foreign objects and water
- 6.10.3 Protection of enclosure against mechanical impact under normal operating conditions
- 6.11 Electromagnetic compatibility (EMC) [Go to Page]
- 6.11.1 General
- 6.11.2 Requirements for immunity
- 6.11.3 Requirements for emission
- 6.11.4 Requirements for transmitted overvoltage (TOV)
- 6.11.5 Requirements for radio interference voltage (RIV)
- 6.11.701 Impact of electric field at rated frequency from other phases
- 6.12 Corrosion
- 6.13 Markings [Go to Page]
- 6.13.1 General
- 6.13.2 Terminal Markings [Go to Page]
- 6.13.2.1 General rules
- 6.13.2.2 Method of marking
- 6.13.2.3 Markings to be used
- 6.13.2.4 Indication of relative polarities
- 6.13.3 Rating Plate Markings
- 6.14 Requirements for LPIT secondary terminal connection [Go to Page]
- 6.14.1 Requirements for digital output connection
- 6.14.1.1 General
- 6.14.1.2 Optical connectors for digital transmitting interface
- 6.14.1.3 Fibre optic terminal box
- 6.14.1.4 Total fibre optic cable length
- 6.14.2 Requirements for analogue output connections [Go to Page]
- 6.14.2.1 Connectors
- 6.14.2.2 Shielding of the secondary circuit
- 6.15 EIT secondary signal noise
- 6.16 Fire hazard
- 6.17 Pressure withstand of gas-filled enclosures
- 6.18 Failure detection of EIT
- 6.19 Operability
- 6.20 Reliability and dependability of electronic part of EIT
- 6.21 Vibration Requirements
- 6.22 Storage climatic conditions withstand capability
- 6.701 Transient response requirements [Go to Page]
- 6.701.1 General
- 6.701.2 Primary short-circuit
- 6.701.3 Step response
- 6.702 Voltage limitation devices requirements
- 6.703 Recommended time interval for the verification of accuracy
- 7 Tests [Go to Page]
- 7.1 General [Go to Page]
- 7.1.1 Classification of tests
- 7.1.2 List of tests
- 7.1.3 Sequence of tests
- 7.1.4 Testing conditions
- 7.2 Type tests [Go to Page]
- 7.2.1 General
- 7.2.1.1 Common requirements
- 7.2.1.2 Information for identification of specimen
- 7.2.1.3 Information to be included in type test reports
- 7.2.2 Temperature-rise test
- 7.2.2.1 General [Go to Page]
- Test procedure
- 7.2.2.2 Measurement of the ambient temperature
- 7.2.2.3 Duration of test
- 7.2.3 Impulse voltage withstand test on primary terminals
- 7.2.3.1 General
- 7.2.3.2 Lightning impulse voltage test on primary terminals
- 7.2.3.2.1 General
- 7.2.3.2.2 Liquid-insulated instrument transformers with Um ≥ 300 kV
- 7.2.3.2.3 Subclause 7.2.3.2.3 of IEC 61869-1:2023 applies.
- 7.2.3.3 Chopped impulse voltage withstand test on primary terminals
- 7.2.3.4 Switching impulse voltage test
- 7.2.4 Wet test for outdoor type instrument transformers
- 7.2.5 Electromagnetic compatibility (EMC) tests
- 7.2.5.1 RIV test
- 7.2.5.2 Immunity test
- 7.2.5.2.1 General
- 7.2.5.2.2 General conditions during immunity tests
- 7.2.5.2.3 Harmonic and interharmonic disturbance test
- 7.2.5.2.4 Slow voltage variation test
- 7.2.5.2.5 Voltage dips and short interruption test
- 7.2.5.2.6 Surge immunity test
- 7.2.5.2.7 Conducted immunity test (150 kHz to 80 MHz)
- 7.2.5.2.8 Conducted immunity tests (0 to 150 kHz)
- 7.2.5.2.9 Electrical fast transient/burst immunity test
- 7.2.5.2.10 Damped oscillatory waves immunity test
- 7.2.5.2.11 Electrostatic discharge test
- 7.2.5.2.12 Power-frequency magnetic field immunity test
- 7.2.5.2.13 Pulse magnetic field immunity test
- 7.2.5.2.14 Damped oscillatory magnetic field immunity test
- 7.2.5.2.15 Radiated, radiofrequency, electromagnetic field immunity test
- 7.2.5.2.16 Voltage ripple on DC power supply
- 7.2.5.2.17 Gradual shutdown and start-up test
- 7.2.5.3 EMC emission tests
- 7.2.6 Test for accuracy
- 7.2.6.1 General [Go to Page]
- 7.2.6.2 Basic accuracy tests
- 7.2.6.3 Additional accuracy tests for protective instrument transformers
- 7.2.6.4 Temperature cycle accuracy test
- 7.2.6.701 Test for accuracy versus frequency
- 7.2.7 Verification of the degree of protection by enclosures
- 7.2.7.1 Verification of the IP coding
- 7.2.7.2 Mechanical impact test
- 7.2.8 Enclosure tightness test at ambient temperature
- 7.2.9 Proof test for the gas-filled enclosure
- 7.2.10 Mechanical tests
- 7.2.11 Voltage withstand test of low-voltage components and secondary terminals
- 7.2.12 Storage climatic environmental tests
- 7.2.12.1 General
- 7.2.12.2 Dry heat test, storage temperature
- 7.2.12.3 Cold test, storage temperature
- 7.2.12.4 Damp heat steady state test
- 7.2.13 Vibration test
- 7.2.14 Durability of markings
- 7.2.15 Tests for accuracy for harmonics
- 7.2.16 Test for anti-aliasing for EIT
- 7.2.701 Test for impact of electric field at rated frequency from other phases
- 7.2.701.1 General
- 7.2.701.2 Test setup for AIS LPVTs
- 7.2.701.3 Test procedure for AIS LPVTs
- 7.2.701.4 Test procedure for three-phase LPVTs for GIS or metal enclosed system
- 7.2.702 Tests for digital output
- 7.2.703 Test for offset
- 7.2.704 Test for noise
- 7.3 Routine tests [Go to Page]
- 7.3.1 Power-frequency voltage withstand tests on primary terminals
- 7.3.2.1 Test circuit and instrumentation
- 7.3.2.2 Partial discharge test procedure
- 7.3.4 Power-frequency voltage withstand test on secondary terminals
- 7.3.5 Power-frequency voltage withstand test for low-voltage components
- 7.3.6 Test for accuracy
- 7.3.7 Verification of markings
- 7.3.8 Enclosure tightness test at ambient temperature
- 7.3.8.1 Closed pressure systems for gas
- 7.3.8.2 Liquid systems
- 7.3.9 Pressure test for the gas-filled enclosure
- 7.3.10 Measurement of capacitance and dielectric dissipation factor
- 7.3.701 Resistance measurement
- 7.4 Special tests [Go to Page]
- 7.4.1 Multiple chopped impulse test on primary terminals
- 7.4.2 Transmitted overvoltage test
- 7.4.3 Internal arc fault test
- 7.4.4 Enclosure tightness test at low and high temperatures
- 7.4.5 Insulation resistance measurement on secondary terminals
- 7.4.6 Corrosion test
- 7.4.7 Fire hazard test
- 7.4.8 Thermo-mechanical endurance test
- 7.4.9 Vibration and shock tests
- 7.4.9.1 General
- 7.4.9.2 Vibration test for primary parts during short-time current
- 7.4.9.3 Vibration tests for primary parts mechanically coupled to a switchgear
- 7.4.9.3.1 General
- 7.4.9.3.2 Vibration during operation
- 7.4.9.3.3 Shock test for parts mechanically coupled to a circuit-breaker
- 7.4.10 Tests for accuracy versus harmonics
- 7.4.11 Seismic qualification
- 7.4.701 Transient response test
- 7.4.701.1 General
- 7.4.701.2 Primary short-circuit test
- 7.4.701.3 Measurement of step response time
- 7.5 Commissioning tests [Go to Page]
- 7.5.1 General
- 7.5.2 Final installation inspection and tests
- 7.5.2.1 General
- 7.5.2.2 Tests on gas-insulated instrument transformers
- 7.5.2.3 Insulation withstand test on LV connection
- 7.5.3 Gas dew point test
- 7.6 Sample tests
- 8 Rules for transport, storage, erection, operation and maintenance [Go to Page]
- 8.1 General
- 8.2 Conditions during transport, storage and installation
- 8.3 Installation [Go to Page]
- 8.3.1 General
- 8.3.2 Unpacking and lifting
- 8.3.3 Assembly
- 8.3.4 Mounting
- 8.3.5 Connections
- 8.3.6 Final installation inspection and tests
- 8.4 Operation
- 8.5 Maintenance [Go to Page]
- 8.5.1 General
- 8.5.2 Responsibilities for the manufacturer
- 8.5.3 Responsibilities for the user
- 8.6 Failure report
- 9 Safety
- 10 Influence of products on the natural environment
- 701 Information to be given with enquiries, tenders and orders
- Annex 7A (informative) Performance of LPVT during transient phenomena in power networks [Go to Page]
- 7A.1 Overview
- 7A.2 General [Go to Page]
- 7A.2.1 Defining primary and secondary voltages
- 7A.2.2 Normal service conditions of the network
- 7A.2.3 Abnormal service conditions of the network
- 7A.2.4 Steady-state conditions
- 7A.3 Transient conditions [Go to Page]
- 7A.3.1 Theoretical considerations
- 7A.3.1.1 Network phenomena
- 7A.3.1.2 Types of transient conditions
- 7A.3.1.3 Equations of up(t) and us(t)
- 7A.3.1.4 Simple modelization of the LPVT
- 7A.3.1.5 Effects of transients on protective relays
- 7A.3.2 Definition of transient error
- 7A.3.3 Test of transient performance
- 7A.3.3.1 Transient performance test for capacitive voltage transformers
- 7A.3.3.2 Transient performance test for low-power voltage transformers
- Annex 7B Correction procedures for low power voltage transformers (informative) [Go to Page]
- 7B.1 Using the ratio and phase correction
- 7B.2 Accuracy class based on corrected secondary signal [Go to Page]
- 7B2.1 Definitions
- 7B2.1.1 Definitions related to accuracy
- 7B2.1.1.1
- 7B2.1.1.2
- 7B2.1.1.3
- 7B2.1.1.4
- 7B2.1.2 Definitions related to secondary signal correction
- 7B2.1.2.1
- 7B2.1.2.2
- 7B2.1.2.3
- 7B2.1.2.4
- 7B2.1.2.5
- 7B2.1.2.6
- 7B2.2 Accuracy based on corrected analogue secondary signal
- 7B2.3 Test for accuracy
- 7B2.3.1 Accuracy tests using corrected analogue secondary signal
- 7B2.3.2 Temperature cycle accuracy test
- 7B2.3.3 Test for impact of magnetic field at rated frequency from other phases
- Annex 7C Impact of electric field at rated frequency from other phases (informative) [Go to Page]
- 7C.1 Extension of validity of test for impact of electric field at rated frequency from other phases for AIS LPVTs
- Annex 7D Type of divider principles covered by IEC 61869-7 (informative) [Go to Page]