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Electricity Quantity & Quality. Hervé Mougeot. Market Overview. Quantity Quality Safety.
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ElectricityQuantity & Quality Hervé Mougeot
Market Overview QuantityQualitySafety • Quantity : Allocate energy usage, detailed cost analysis, cut energy costs, negotiate better energy contracts, demand control and peak saving, information for improving infrastructure, load curtailment and price response, power factor correction. • Quality : Availability, troubleshooting, productivity, preventive maintenance, quality statistics, information for improving infrastructure • Safety : protect people and property Quality U=Z I Quantity Safety
Electrical Network Production Transmission Distribution Users LV HV MV Network = Share of the electricity ... and the pollution. Example : The pollution generated from a disturbing load will be distributed to the neighbors more or less attenuated depending on the network impedance.
ElectroMagnetic Compatibility Immunity secured load Immunity standard load Disturbance level EN50160 Compatibility Emission on the network Emission from single load IEC1000-3-x t
Compatibility Transient Swell Dip
= U V 3 3 Phases System U31 V3 U23 V1 V2 U12
Electrical Disturbances low frequency, conducted • Voltage variations • Voltage Dips • Interruptions • Voltage Swells • Flicker • Harmonics • Inter harmonics • Transients • Frequency • Unbalance • Amplitude • Wave Shape • Frequency • Symmetry
Ueff %Un u 100 90 ΔU = 30% (depth) 70 t ΔT = 112ms (durée) U (amplitude) t (ms) 0 40 80 120 160 200 240 280 0 40 80 120 160 200 240 280 Voltage Dips
Ueff %Un u ΔT = 83ms (duration) t 1 t (ms) 0 40 80 120 160 200 240 280 0 40 80 120 160 200 240 280 Interruptions 100
8,8Hz Flicker
10 3% / 0,757 1 0,29% / 1052 Nombre de variations par minute 1000 1 10 0,1 100 Flicker Pst = 1 , cas des variations rectangulaires
+ = = + 1 3 5 n Harmonics
U1 vIE IE ZA 2vIE IE vIE U2 UG SA TU = = (1-Phase-Load) U3 UM SK Unbalance
Disturbances Dips, Swell, Interruptions Flicker Harmonics Transients Frequency Variation Unbalance
What to measureEN 50160Voltage characteristics in public distribution systems
EN 50160 Parameters • Voltage Variations • Flicker Pst/Plt • Harmonics order 2 to 25, THD (40) • Signalling (ripple control) voltages • Frequency • Unbalance • Voltage dips and swells • Interruptions Measurement over 1 week
To measure according EN 50 160 = 150.000 data to analyze for 1 week, for 1 point !
Amplitude standard 100% 95 % number of measuring values
Amplitude standard 100% 95 % number of measuring values
Amplitude standard 100% 95 % number of measuring values
Amplitude standard 100% 95 % number of measuring values
How to measureIEC 61000-4-30Testing and measurement techniques – Power Quality measurement methods
Measurement techniques Continuity / Change
Permanent average values recording – Triggered values recording Permanent / Trigger
FFT A/D X² Events / Trend 8 256 s/c 16-Bit T A/D FIFO (4) T Transient 1 MHz 12-Bit X
Event recording Acquisition Treatment Characterization Detection Evaluation Classification Measure Analyze Archive Recording
Derived from ½ cycles • (3.22 1cycle refreshed each 1/2cycle, 20msec) • Reference is either Udin (LV) or • sliding voltage (MV, HV) • ½ cycles must be synchronised on reference channel Voltage Dip / Swell (5.4) Voltage Interruption (5.5)
Time aggregation • 10/12 cycle(200msec) at 50/60Hz, 150/180 cycles(3sec) at 50/60Hz, interval time varies with actual frequency • 10min,2h interval sync to clock (including defined algorithm from cycle to time aggr.) • Aggregations are performed using the square root of arithmetic mean of squared input • All are non-gapping, 150/180 aggregated out of 15x10/12; 2h out of 12x10min Long term recording
10/12 cycle(200msec) at 50/60Hz, interval time varies with actual frequency • 150/180 cycles(3sec) at 50/60Hz, interval time varies with actual frequency • 10min interval sync to clock (including defined algorithm from cycle to time aggr.) • 2h interval sync to clock (including defined algorithm from cycle to time aggr.) • Aggregations are performed using the square root of arithmetic mean of squared input • All are non-gapping, 150/180 aggregated out of 15x10/12; 2h out of 12x10min Time aggregation (4.4/4.5)
Time aggregation (4.4/4.5) Zero Crossing of Fundamental (filtered) 10 150 Synchronised Clock ±20msec 10min 2h
For Timestamp of Events and • Synchronisation of the 10min and 2h interval • Accuracy of timestamp: ±20/16,7msec at 50/60Hz • (Realisation with e.g.: GPS or DCF 77 sync) Time Clock Uncertainty (4.6)
Only one event extracted out of different events • (dip, swell and interruption influences also frequency, flicker…) Flagging (4.7)
Obtained every 10sec from the reference channel • Synchronise the sampling frequency of the system • no fix sampling frequency 'possible' (e.g.: PLL) • Accuracy of power frequency measurement ±0,01Hz Power Frequency (5.1)
Accuracy without accessory: ± 0,1% of Udin • (Udin declared input voltage) • (same for current, but today only recommended) Accuracy for voltage (5.2)
Flicker algorithm according to IEC 61000-4-15 Flicker (5.3)