Novità sulla IEC ; -10; -12

Transcription

1 Novità sulla IEC ; -10; -12 DIPL. ING. MARKUS FUHRER

2 Content Recently revised standards IEC Ed Impulse magnetic field IEC Ed Damped oscillatory magnetic field immunity test IEC Ed Ring Wave immunity tests IEC Ed. 2.0 CDV 2018 Damped oscillatory wave immunity test 2

3 IEC Impulse magnetig field immunity test Ed

4 IEC Phenomenon Sources Pulsed magnetic fields are generated by lightning strikes in buildings and other metallic structures such as antenna masts, ground connections and ground plane as well as conducted transients in the event of faults in low, medium and high voltage systems. This standard specifies the immunity requirements for equipment exposed to magnetic fields mainly occurring in the following environments, such as: - Industrial installations, - power stations, - railway installations, - medium-voltage and high-voltage substations The applicability of this standard to devices installed in different locations is determined by the presence of the phenomenon. This standard does not take into account interference caused by capacitive or inductive coupling in cables or other parts of the field installation. Other IEC standards dealing with conducted disturbances cover these aspects. 4

5 IEC Test Levels The preferred ranges of test levels are given in Table 1 Table 1 Test Levels IEC Level x a ) Pulse magnetic field strenght (A/m peak) Special a "X" can be any level, above, below or in between the others. The level shall be specified in the dedicated equipment specification. NOTE The magnetic field strength is expressed in A/m; 1 A/m corresponds to a free space magnetic flux density of 1,26 μt. The test levels shall be selected according to the installation conditions; classes of installation are given in Annex C. 5

6 IEC Generator and Waveform The test system consists of the Surge generator (hybrid generator) according to IEC and the induction coil for table-top devices and additionally for floor-standing devices of a reference ground plate. The generator must be able to deliver the required pulse current to the induction coils (1 m x 1 m or 1 m x 2.6 m) mentioned in chapter 6.3. The waveform is specified as short-circuit current and should therefore be measured with the generator without an induction coil connected. Figure 1 Simplified circuit of the combination wave generator MS 100N INA 701 6

7 Generator Polarity Phase shift Repetition rate Short circuit Peak-output current Waveform of current impulse see table 2 and figure 2 Short circuit peak current tolerance ± 10 % positive and negative in range of 0 to 360 relative to the AC phase angle to the EUT with a tolerance of ± per minute or faster 100 A to 1000 A or the required test level divided by the coil factor IEC Front time Tf μs Front time Tf μs Short circuit current Tf = 1,25 Tr = 8 μs ± 20 % Td = 1,18 Tw = 20 μs ± 20 % Table 2 Definition of the der waveform parameter 8/20 μs Figure 2: Waveform of short-circuit current (8/20 μs) at the output of the generator 7

8 IEC Calibration of the test system The characteristics of the test system shall be calibrated by current measurement. Check the output current with the generator connected to the antenna. The 18 μf capacitor is connected externally if it is not installed internally in the generator. The connection is made by twisted conductors or coaxial cables with a length of up to 3 m and a suitable cross-section. Front time Tf Duration Td System mit 1 m x 1 m Standardantenne Tf = 1,25 Tr = 8 μs + 2,4-0.8 Td = 1,18 Tw = 20 μs μs System mit 1 m x 2,6 m Standardantenne Tf = 1,25 Tr = 8 μs μs Td = 1,18 Tw = 20 μs μs Table 3: Specifications of the waveform time parameters of the test system 8

9 IEC Test setup Test equipment The following equipment is part of the test setup: - Equipment under test (EUT); - auxiliary equipment (AE) when required; - Cables (specified type and length); - Surge Generator (CWG, combination wave generator) with an internal or external 18 μf capacitor; - Induction coil (1 m x 1 m or 1 m x 2,6 m); - Reference ground plane in case of testing floor standing equipment; Verification of the test instrumentation The purpose of verification is to ensure that the test setup is operating correctly. The test setup includes: - the combination wave generator; - the induction coil; - the interconnection cables of the test equipment. To verify that the system is functioning correctly, the following signal should be checked: - surge impulse present at the induction coil terminals. It is sufficient to verify that the surge is present at any level by using suitable measuring equipment (e.g. current probe, oscilloscope). 9

10 IEC Test setup for table top equipment The EUT shall be placed on a non-conductive table. The induction coil shall be positioned in three orthogonal orientations. Antenna Test volume max. EUT dimension 1 m x 1 m 0,6 m 0,6 m 0,5 m (L x B x H) 1 m x 2,6 m 0,6 m 0,6 m 2 m (L x B x H) An RGP is not required below the EUT. The induction coil shall be kept at least 0,5 m from any conducting surfaces, e.g. the walls and floor of a shielded enclosure. Figure 4 IEC Example of a table top equipment Proximity method When an EUT does not fit into the induction coil of 1 m x 2,6 m, either the proximity method can be used. It is not necessary to maximize the impact of cables during this test. The proximity of the cables to the loop antenna can impact the results so the cables shall be routed to minimize this impact. The minimized cabling dimension shall be incorporated into the determination of the maximum size of EUT that can be tested. 10

11 IEC Test setup for floor standing equipment Die Test equipment are isolated from the reference ground(grp) at the ground. Reference ground (RGP) - Thickness 0,65 mm - Min size of 1 m x 1 m. Antenna test volume 1 m x 2,6 m 0,6 m x 0,6 m x 0,6 m x 2 m (L x B x H). Standard antenna; GRP may be the short side for large devices. 1 m x 1 m permissible for floor standing devices with dimensions up to 0.6 m x 0.6 m Helmholtz This antenna was deleted in Ed. 2 Figure 5 Example of test setup for floor standing equipment showing the horizontal orthogonal plane EUT The EUT must be isolated from the reference ground. (as with EFT test) Standing devices (e.g. racks) where the upper edge of the test object is more than 0.75 m from the RGP must be tested in several positions, but the induction coil shown in Fig. 5 must not be placed below 0.5 m. Figure 6 Example of test setup for floor standing equipment showing the vertical orthogonal plane 11

12 IEC Test setup for impulse magnetic field applied in-situ Proximity method In-situ testing is generally the only practical test method available for large machinery or similar equipment. It is not necessary to maximize the impact of cables during this test. The proximity of the cables to the loop antenna can impact the results so the cables shall be routed to minimize this impact. The minimized cabling dimension shall be incorporated into the determination of the maximum size of EUT that can be tested. NEW Ed.2 In situ test The proximity method may be the only practical test method without the RGP in place. Figure 7 gives an example for a test setup for in-situ testing. During in-situ testing, an RGP is normally not available. Figure 7: Example of test setup using the proximity method Procedure: Distance: GRP: H-field: Approach with 1 m x 1 m antenna to EUT EUT Antenna (10 ± 1) cm, Isolation to the antenna is guaranteed The reference mass is usually not available Same as in the middle of the standard induction coil 12

13 IEC Test procedure General The test procedure includes : - the verification of the test instrumentation with current probe and scope; - The establishment of the laboratory reference conditions; Unless otherwise specified in the product standards, the climatic conditions in the laboratory are within the limits specified for the operation of the test specimen by the respective manufacturers. In case of condensation on the EUT, the tests must not be carried out. - the confirmation of the correct operation of the EUT; - the execution of the test; - the evaluation of the test results (see clause 9). NEW Ed.2 13

14 IEC Execution of the test Test procedure NEW Ed.2 The test shall be performed according to a test plan which shall specify the test setup, including: - test level; - number of impulses (for each orthogonal orientation): number of impulses unless otherwise specified by the relevant standard: - for d.c. powered EUT 5 positive and 5 negative impulses; - for 1- and 3- phase a.c. powered EUT 20 positive and 20 negative impulses without phase synchronization; - impulse repetition 60s or faster impulse per minute (Product Committees may specify this repetition rate); - representative operating conditions of the EUT; - Three orthogonal orientations of the magnetic field in case of table top and floor standing equipment; - Locations of the induction coil relative to the EUT (test points). For most products, phase synchronization may not be appropriate; therefore Product Committees should decide on the need of phase synchronization for their products. NOTE 1 The application of tests with different phase angles may be more critical for equipment with inverter technology. NOTE 2 Special safety considerations may be needed when using the generator s CDN output. 14

15 IEC Execution of the test Example Test setup of a rectangular coil (1m x 1m) Surge generator EUT s Twisted cable Reference GND -non magnetic 1m x 1m Coil 15

16 IEC Measuring uncertainty MU Table D.1 - Example of uncertainty budget for surge current front time (Tf) NEW Ed.2 Table D.2 - Example of uncertainty budget for peak of surge current (Ip) Table D.3 - Example of uncertainty budget for current impulse width (Td) 16

17 IEC Test setup with two antennas (Annex F) NEW in Ed.2 Appendix F shows an example of Helmholtz coils with two 1 m x 1 m standard induction coils connected in parallel to the surge generator. This double induction coil provides better field homogeneity for testing larger EUT. The calibration of the test system is done with a current measurement (Fig. F.1), which should be identical in both coils. Figure F.1 Calibration of a system with double standard coils Table F.1 Peak current in system with two antennas a= 0.8 m 17

18 Content Recently revised standards IEC Ed Impulse magnetic field IEC Ed Damped oscillatory magnetic field immunity test IEC Ed Ring Wave immunity tests IEC Ed. 2.0 CDV 2018 Damped oscillatory wave immunity test 18

19 IEC Damped oscillatory magnetic field immunity test Ed

20 IEC Phenomenon This phenomenon is typical for switching operations of isolators in free-field installations in high and medium voltage distribution stations and represents disturbances as they occur in busbars. The opening and closing of HS disconnectors leads to transients, with rise times in the order of several tens of nanoseconds. The transient current peak, which generates the magnetic field of this standard, is directly related to the peak voltage on the busbars and their characteristic impedance. Due to reflections, oscillations occur in outdoor substations depending on the length of the conductor bars (several dozen meters to a few hundred meters). The oscillation frequency of 1 MHz is considered representative, can also be at 100 khz for large high-voltage systems. The repetition frequency ranges from a few hertz to a few khz, with the standard specifying repetition rates of 40/s and 400/s. In industrial plants, oscillating transients can be caused by switching operations in the power grid and by transients from electrical devices. The magnetic field of the slow-damped current pulse of IEC is used for the test. 20

21 IEC Test levels The preferred ranges of test levels are given in Table 1 Table 1 Test Levels IEC Level Damped oscillatory magnetic field strength [A/m] (Peak) 1 not applicable 2 not applicable x a Special NOTE - The magnetic field strength is expressed in A/m; 1 A/m corresponds to a free space induction of 1,26 μt. a "x" can be any level, above, below or in between the others. This level, as well the duration of the test, shall be specified in the dedicated equipment specification. The test levels shall be selected according to the installation conditions; classes of installation are given in Annex B. 21

22 IEC Test system Revised in Ed.2 The test system comprises the damped oscillatory wave generator and the induction coil for a table-top test setup and, in addition, a RGP for a floor-standing test setup. The damped oscillatory wave generator shall be able to deliver the required impulse current to the induction coils specified in 6.3. (1 m x 1 m oder 1 m x 2,6 m). NOTE For this application, a modified version of a damped oscillatory wave generator similar to the generator mentioned in IEC is used as a current source. The waveform is specified as a short-circuit current and shall be measured with the induction coil connected. U High voltage source Rc Charging resistor C Control duration L Coil oscillation circuit S 1 Frequency selector S 2 Switch duration selector C 1, C 2 Capacitor oscillation circuit (switchable from 0,1 MHz or 1 MHz) 22

23 IEC Waveform The waveform is specified as short-circuit current and must be measured on a connected induction coil. Calibration items Oszillation frequency 100 khz 1 MHz Oszillation period T = 10 μs ± 1 μs T = 1 μs ± 0,1 μs Repetition rate of theimpulses T rep = 25 ms ± 2,5 ms (40/s) T rep = 2,5 ms ± 0,25 ms (400/s) Decay of one pulse D r1 = I(Pk 5 ) I (Pk 1 ) > 50 % D r2 = I(Pk 10 ) I (Pk 1 ) < 50 % D r1 = I(Pk 5 ) I (Pk 1 ) > 50 % D r2 = I(Pk 10 ) I (Pk 1 ) < 50 % NEW in Ed.2 Bisherige Auswertung Ed. 1 23

24 Standard induction coil IEC For the two single turn standard coils 1 m x 1 m and 1 m x 2,6 m, the field distribution is known and shown in Annex A. Therefore, no field verification or field calibration is necessary; the current measurement as shown in Figure 4 is sufficient. The induction coil shall be made of copper, aluminum or any conductive non-magnetic material, of such cross-section and mechanical arrangement as to facilitate its stable positioning during the tests. The antennas are suitable as described in the basic standards IEC and IEC Field distribution of a standard antenna (Annex A) NEW in Ed.2 Field distribution of the 1 m x 1 m induction coil Field distribution of the 1 m x 2.6 m induction coil 24

25 IEC Verification The characteristics of the test system shall be verified by current measurement. Check the output current with the generator connected to the standard induction coil (antenna). The connection is made by twisted wires or coaxial cables with a length of up to 3 m and a suitable cross-section. Test Level X NOTE 1 NOTE 2 System with 1 m x 1 m standard induction coil not applicable not applicable Special/0,9 Peak current I ± 20 % [A] System with 1 m x 2,6 m standard induction coil not applicable not applicable see note 2 Special/0,66 The values 0,9 and 0,66 are the calculated coil factors of standard induction coils. The calculated value is 152; however, there is currently no commercial generator available. Verification with current measurement as per figure 4 IEC The calibrations shall be performed at all levels, which are used by laboratories. The calibrations shall be carried out with a current probe (0.1 V/A) and oscilloscope or other equivalent measurement instrumentation with 10 MHz minimum bandwidth. 25

26 IEC Test setup Test equipment The following equipment is part of the test setup: - equipment under test (EUT); - auxiliary equipment (AE) when required; - cables (specified type and length); - damped oscillatory wave generator ; - standard induction coil (1 m x 1 m or 1 m x 2,6 m); - reference ground plane (RPG) in case of testing floor standing equipment; Verification of the test equipment The purpose of verification is to ensure that the test setup is operating correctly. The test setup includes: - the damped oscillatory wave generator ; - the induction coil; - the interconnection cables of the test equipment. To verify that the system is functioning correctly, the following signal should be checked: - surge impulse present at the induction coil terminals. It is sufficient to verify that the surge is present at any level by using suitable measuring equipment (e.g. current probe, oscilloscope). 26

27 IEC Test setup for table top equipment The EUT shall be placed on a non-conductive table. The induction coil shall be positioned in three orthogonal orientations. Antenna Test volume max. EUT dimension 1 m x 1 m 0,6 m 0,6 m 0,5 m (L x B x H) 1 m x 2,6 m 0,6 m 0,6 m 2 m (L x B x H) An RGP is not required below the EUT. The induction coil shall be kept at least 0,5 m from any conducting surfaces, e.g. the walls and floor of a shielded enclosure. Figure 5 IEC Example of a table top equipment 27

28 IEC Test setup for floor standing equipment The Test equipment is isolated from the reference ground(grp) at the ground. Reference ground (RGP) - Thickness 0,65 mm - Min size of 1 m x 1 m. Antenna test volume 1 m x 2,6 m 0,6 m x 0,6 m x 0,6 m x 2 m (L x B x H). Standard antenna; GRP may be the short side for large devices. 1 m x 1 m permissible for floor standing devices with dimensions up to 0.6 m x 0.6 m Helmholz This antenna was deleted in Ed. 2 Figure 6 - Example of test setup for floor standing equipment showing the horizontal orthogonal plane EUT The EUT must be isolated from the reference ground. (as with EFT test) Standing devices (e.g. racks) where the upper edge of the test object is more than 0.75 m from the RGP must be tested in several positions, but the induction coil shown in Fig. 5 must not be placed below 0.5 m. Figure 7 - Example of test setup for floor standing equipment showing the vertical orthogonal plane. 28

29 IEC Test setup for damped oscillatory field applied in-situ Proximity method In-situ testing is generally the only practical test method available for large machinery or similar equipment. It is not necessary to maximize the impact of cables during this test. The proximity of the cables to the loop antenna can impact the results so the cables shall be routed to minimize this impact. The minimized cabling dimension shall be incorporated into the determination of the maximum size of EUT that can be tested. In-situ tests The proximity method may be the only practical test method without the RGP in place. Figure 7 gives an example for a test setup for in-situ testing. During in-situ testing, an RGP is normally not available. Figure 8: Example of test setup using the proximity method Procedure: Distance: GRP: H-field: Approach with 1 m x 1 m antenna to EUT EUT Antenna (10 ± 1) cm, Isolation to the antenna is guaranteed The reference mass is usually not available Same as in the middle of the standard induction coil 29

30 IEC Execution of the test The verification of the pulse shape (current measurement) should preferably be carried out before the test. The test is carried out according to the test plan in which the test set-up is specified, including : - test level; - Test duration (not less than 2 s); - oscillation frequencies; - representative operating conditions of the EUT; - Orientations of the field; - Number of test points; - locations of the standard induction coil relative to the EUT (test points); - selection and justification of test points (recommended are areas of EUT susceptible to damped oscillatory magnetic fields). NOTE Product Committees may apply longer test durations, if appropriate for their products. The test duration shall be applied only one time for each orientation. 30

31 IEC Measuring uncertainty MU ( ANNEX D) NEW in Ed.2 The revised standards contain new information and calculation principles for determining the measurement uncertainty of the current pulse. This calculation is explained in detail in the appendix, so that the user can use this table as a reference during an audit. Symbol Estimate Unit Error bound Unit PDF* Divisor u(xi) ci Unit ui(y) Unit VPR 0,115 V 0,0002 V triangular 2,45 0, /Ω A RT 0,001 Ω 0,00005 Ω rectangular 1,73 0, A/Ω 3,33 A δr 0 1 0,03 1 normal (k=1) 1,00 0, ,5 A 3,46 A δv 0 1 0,02 1 rectangular 1,73 0, ,5 A 1,33 A ß 638 khz 71 khz rectangular 1,73 40,99 0,00148 A/kHz 0,061 A B khz 1000 khz rectangular 1,73 577,4-0,00009 A/kHz A uc(y) = Σui(y)2 4,99 A U(y) = 2 uc(y) 9,98 A y 115 A Expressed in % of 115 A 8,6 % Example of uncertainty budget for the peak of the damped oscillatory current impulse (Ip) 31

32 Content Recently revised standards IEC Ed Impulse magnetic field IEC Ed Damped oscillatory magnetic field immunity test IEC Ed Ring Wave immunity tests IEC Ed. 2.0 CDV 2018 Damped oscillatory wave immunity test 32

33 IEC Ring Wave immunity tests Ed

34 IEC Phänomem The "Ring wave" simulates interference in low-voltage cables induced by switching electrical grids and reactive loads. This results in disturbances in supply networks as well as breakdowns in insulation or voltage flashovers. It is one of the most common phenomena in high, medium and low voltage grids as well as in their control and signal lines. The propagation in the lines is always a consequence of reflections caused by impedance changes in protective devices and filters. The rise times of the pulse are in the range of some 10 ns up to fractions of 1 μs with a duration of 10 ms-100 ms. The ring wave is defined with a rise time of 0.5 μs and a damped oscillation of 100 khz. The interference pulse is seen as a typical and frequently occurring interference variable and is used in products for use in power supply systems and railway applications. 34

35 Test levels Table 1: Test levels The preferred test levels for the ring wave applicable to power, signal and control ports of the equipment, are given in Table 1. The test level is defined as the voltage of the first peak (maximum or minimum) in the test waveform (Pk1 in Figure 1). IEC Table 1: Test levels for ring wave Figure 1: Waveform of the ring wave 35

36 Generator The generator output shall have the capability to operate under short-circuit conditions. A block diagram of a representative ring wave generator is shown in Figure 2. IEC Bild 2: Schema vom Ring wave Generator Generator impedance values R3: 30 Ω for unshielded interconnection lines. R4: 12 Ω for a.c./d.c. power ports and shielded interconnection lines 36

37 IEC Performance characteristics of the ring wave generator Characteristic of the Ring wave Generator: open circuit voltage Pk1: 250 V 6000 V ± 10 %; voltage rise time T1: 0.5 µs ± 30 %; current rise time T1: 0.2 µs up to 1 µs oscillation frequency 1/T: 100 khz ± 10 %; repetition rate: 1/ min. or faster (1-999 s) decay (voltage only): ratio Pk2 to Pk1 40% - 110% ratio Pk3 zu Pk2 40% - 80% ratio Pk4 zu Pk3 40% - 80% no requirements for Pk5 onwards output impedance: 12 Ω, 30 Ω ± 20% switchable open circuit voltage : Pk1 value, 250 V to 4.4 kv ± 10 %; polarity 1st half period: positive,negative, alternating phase synchronization: resolution ± 10 (1 ) 37

38 IEC Verification Table 2 Relationship between peak open-circuit voltage and peak short-circuit current NEW Ed.3 Measurement of the generator parameter: - open-circuit and short-circuit measurement for all test levels - All parameters mentioned in section 6.1.3, with the exception of the phase shift and the repetition rate, must be verified at the output of the generator. The phase shift must be verified at the output of the CDN at 0, 90, 180 and 270 with a polarity. Requirements for the measuring system: Bandwidth : > 20 MHz Impedances: > 10 kω, short circuit < 0.1 Ω 38

39 IEC Coupling networks NEW Ed.3 Figure 4 Figure 5 Figure 6 Figure 7 1 ph or d.c.: Bild 4 3 Phasen: Bild 6 1 ph or d.c.: Figure phase: Figure 7 Figure 11 Figure 8 Figure 9 or 10 Figure 11 Figure 8 Figure 9 or 10 39

40 Verification of CDN The requirements for the measuring instruments are the same for the calibration of the generator and CDN. The peak amplitude Pk1 and the rise time are for the open circuit voltage and the short-circuit current at the CDN output. For the open circuit voltage, the oscillation frequency must also be checked. Ed3 defines the calibration procedure for all CDNs. For CDN above 16 A, the tolerances in Table 3 are applicable. - Residual voltage at the open EUT supply input between the applied lines and the earth in no-load condition. The higher value of: 15% of the maximum test voltage applied or twice the nominal peak voltage of the CDN. - Decoupling inductivity: max. 1.5 mh, where du of the CDN: < 10% The standard defines for all CDN the couplings and the values to be measured and their tolerances. IEC NEW Ed.3 Table 3: Ring wave specification at the EUT power port of the CDN 40

41 IEC Verification of the CDN Table 4 Summary of calibration process for CDNs for unsymmetrical interconnection lines NEW Ed.3 Table 5 Ring wave waveform specifications at the EUT port of the CDN for unsymmetrical interconnection lines 41

42 IEC Verification of the CDN Table 6 Summary of calibration process for CDNs for symmetrical interconnection lines NEW Ed.3 Table 7 Ring wave waveform specifications at the EUT port of the CDN for symmetrical interconnection lines 42

43 IEC Test setup Coupling to power lines Example: lines line-to-line coupling Example: lines line-to-ground coupling OCS 500N6 43

44 IEC Test setup Coupling to connection lines shielded / unshielded Example: Coupling to shielded cables with shield at both ends Example: Coupling to - unbalanced unshielded cables - shielded cables with shield at one end compact NX7 44

45 IEC Test setup Coupling to symmetrical connection lines NEW Ed.3 Example: Coupling to shielded cables with shield at both ends Example: Coupling to symmetrical unshielded high-speed data lines OCS 500N6F 45

46 IEC Execution of the test The test procedure includes : - verification of the test equipment; - Ringwave generator; CDN; connection cable; measuring instruments; - to verify: Ringwave at CDN output - Check at each level without EUT. An internal laboratory reference value is permitted. - the definition of laboratory reference conditions; with regard to climatic conditions - confirmation that the EUT is operating properly; - the execution of the test according to the test plan; - test level - number of Ringwave pulses on each coupling path (if not specified otherwise) - d.c. Connections and connecting lines 5 positive and 5 negative - a.c. Connections 5 positive and 5 negative pulses each at 0º, 90º, 180º and 270º; - Time between two pulses: 1 min or faster; - representative EUT operating conditions; - EUT ports to be tested; - test generator with the selected impedance; (12 a.c./d.c shielded line, 30 unshielded line) - Test severity due to non-linear components from the lowest to the required. - the evaluation of the test results (see point 9). NEW Ed.3 46

47 IEC Measuring uncertainty MU( ANNEX D) Table D.1 Example of uncertainty budget for ring wave rise time (T1). NEW Ed.3 Table D.2 Example of uncertainty budget for the peak of the short circuit current of the ring wave (Pk1). 47

48 Thank you for your attention!