Part 3 Limits- Section 3 : Limition of voltage fluctuations and flicker In low-voltage supply systems for equipment with rated current

Part 3 Limits-Part 3 Limits-

Section 3 : Limition of voltage fluctuations and Section 3 : Limition of voltage fluctuations and flicker In low-voltage supply systems for equipflicker In low-voltage supply systems for equipment with rated current <16Ament with rated current <16A

Group 7AGroup 7A

50262339 Wong Yuk Tung50262339 Wong Yuk Tung

50247510 Ching Chun50247510 Ching Chun

50204951 Eddie50204951 Eddie

ObjectivesObjectives

It specifies limits of voltage changes which It specifies limits of voltage changes which may be produced by an equipment tested may be produced by an equipment tested under specified conditions and gives under specified conditions and gives guidance on methods of assessment.guidance on methods of assessment.

ObjectivesObjectives

It is applicable to electrical and electronic It is applicable to electrical and electronic equipment having an input current up to equipment having an input current up to and including 16A per phase and intended and including 16A per phase and intended to be connected to public low-voltage to be connected to public low-voltage distribution system of between 220V and distribution system of between 220V and 250V at 50Hz line to neutral.250V at 50Hz line to neutral.

Test CircuitTest Circuit

Voltage Fluctuations and Flicker Voltage Fluctuations and Flicker

Voltage Fluctuation Voltage Fluctuation A series of voltage changes or a continuous A series of voltage changes or a continuous

variation of the r.m.s. voltagevariation of the r.m.s. voltage

FlickerFlicker Impression of unsteadiness of visual Impression of unsteadiness of visual

sensation induced by a light stimulus whose sensation induced by a light stimulus whose luminance or spectral distribution fluctuates luminance or spectral distribution fluctuates with time.with time.

Assessment of voltage fluctuations and Assessment of voltage fluctuations and flickerflicker

1. Assessment of a relative voltage chang1. Assessment of a relative voltage change, “d”e, “d”

2. Assessment of the short-term flicker val2. Assessment of the short-term flicker value,Pue,Pstst

3. Assessment of long-term flicker value,P3. Assessment of long-term flicker value,Ptt

tt

1. Assessment of a relative voltage change1. Assessment of a relative voltage change

Voltage change waveform at the terminals Voltage change waveform at the terminals of the EUTof the EUT

difference difference ΔΔU of any 2 successive values U of any 2 successive values of the phase-to-neutral voltages U(tof the phase-to-neutral voltages U(t11) and ) and

U(tU(t22))

ΔΔU = U(tU = U(t11) - U(t) - U(t22))

2. Assessment of the short-term flicker value, 2. Assessment of the short-term flicker value, PPstst

The flicker severity evaluated over a short The flicker severity evaluated over a short period (in minutes); Pperiod (in minutes); Pstst=1 is the =1 is the

conventional threshold of irritabilityconventional threshold of irritability(amendment 1to IEC 868)(amendment 1to IEC 868)

Assessment method for PAssessment method for Pstst

Types of voltage fluctuationTypes of voltage fluctuation Method of evaluating Method of evaluating PPstst

All voltage fluctuations (on-line All voltage fluctuations (on-line evaluation)evaluation)

Direct measurementDirect measurement

All voltage fluctuations where U(t) All voltage fluctuations where U(t) is defincdis defincd

Simulation Simulation Direct measurementDirect measurement

Volatge change waveform Volatge change waveform according to fig. A to C with an according to fig. A to C with an occurrence rate less than 1 per occurrence rate less than 1 per secondsecond

Analyist methodAnalyist method Simulation Simulation Direct measurementDirect measurement

Rectangular voltage changes Rectangular voltage changes at equal intervalsat equal intervals

Use of the PUse of the Pstst=1 =1

curvecurve

2.1 Flickermeter2.1 Flickermeter

All types of voltage fluctuations may be All types of voltage fluctuations may be assessed by direct measurement using assessed by direct measurement using flickermeterflickermeter

2.2 Simulation method2.2 Simulation method

When the relative voltage change When the relative voltage change waveform d(t) is known, Pst can be waveform d(t) is known, Pst can be evaluated using a computer simulation.evaluated using a computer simulation.

2.3 Analytical method2.3 Analytical method

Shape factors F for double-step and ramp-voltage characteristicsShape factors F for double-step and ramp-voltage characteristics

Shape factors F for rectangular and triangular voltage characteristicsShape factors F for rectangular and triangular voltage characteristics


Shape factors F for motor-start voltage characteristics having various front times.Shape factors F for motor-start voltage characteristics having various front times.


The value of PThe value of Pstst obtained using this obtained using this

method is expect to be within +/- 10% of method is expect to be within +/- 10% of the result which would be obtained by the result which would be obtained by direct measurement (reference method).direct measurement (reference method).

This method is not recommended if the This method is not recommended if the time duration between the end of one time duration between the end of one voltage change and the start of the next is voltage change and the start of the next is less than 1s.less than 1s.


2.4 Use of P2.4 Use of Pstst = 1 curve = 1 curve

For rectangular voltage changes of the same For rectangular voltage changes of the same amplitude “d” separated by equal time intervals, amplitude “d” separated by equal time intervals,

Curve may be used to deduce the amplitude Curve may be used to deduce the amplitude corresponding to Pcorresponding to Pstst=1 for a particular rate of =1 for a particular rate of

repetition; repetition;

This amplitude is called dThis amplitude is called d limlim. .

The PThe Pstst value corresponding to the voltage value corresponding to the voltage

change “d” is then given by Pchange “d” is then given by Pstst =d/d =d/dlimlim

2.4 Curve for P2.4 Curve for Pstst = 1 = 1

3. Assessment of long-term flicker value, P3. Assessment of long-term flicker value, Pltlt

The flicker severity evaluated over a long The flicker severity evaluated over a long period (a few hours) using successive Pperiod (a few hours) using successive Pstst

values. values.

e.g. Lighting equipmente.g. Lighting equipment Shall be tested with a lamp of the that power Shall be tested with a lamp of the that power

for which the equipment is ratedfor which the equipment is rated

6. Test Condition 6. Test Condition 6.1 General6.1 General

No need for equipments that are unlikely to No need for equipments that are unlikely to produce significant voltage fluctuations or flicker.produce significant voltage fluctuations or flicker.

Test setup:Test setup: Test supply voltageTest supply voltage Reference ImpedanceReference Impedance Equipment Under TestEquipment Under Test Flickermeter if necessaryFlickermeter if necessary

Test CircuitTest Circuit

6. Test Condition6. Test Condition 6.2 Measurement Accuracy 6.2 Measurement Accuracy

ToleranceTolerance

current (I): +/-1%current (I): +/-1%

relative voltage change (d): +/-8% (w.r.t drelative voltage change (d): +/-8% (w.r.t dmaxmax))

total impedance: +/-8% (excluding EUT)total impedance: +/-8% (excluding EUT)

6. Test Condition6. Test Condition6.3 Test Supply Voltage6.3 Test Supply Voltage

Test supply voltage (o/c volt) shall be the rated Test supply voltage (o/c volt) shall be the rated voltage of EUT.voltage of EUT.

230V single-phase / 400V three-phase for 230V single-phase / 400V three-phase for equipment stated with voltage range.equipment stated with voltage range.

Tolerance:Tolerance: Voltage: +/-2% of nominal valueVoltage: +/-2% of nominal value Frequency: 50Hz +/- 0.5%Frequency: 50Hz +/- 0.5%

6. Test Condition6. Test Condition6.5 Observation Period6.5 Observation Period

For all assessments,For all assessments,

(flickermeter, simulation, analytical)(flickermeter, simulation, analytical)

for Pst, Tp = 10minsfor Pst, Tp = 10mins

for Plt, Tp = 2hrs.for Plt, Tp = 2hrs.

Observation period shall include part of the Observation period shall include part of the whole operation cycle in which the EUT whole operation cycle in which the EUT produces the most unfavorable sequence of produces the most unfavorable sequence of voltage changes.voltage changes.

6. Test Condition6. Test Condition6.5 Observation Period6.5 Observation Period

Short term flicker measurementShort term flicker measurement Operation repeated continuously, unless Operation repeated continuously, unless

otherwise specified.otherwise specified. Also include time to restart the equipmentAlso include time to restart the equipment

Long term flicker measurementLong term flicker measurement Operation not repeated, unless otherwise Operation not repeated, unless otherwise

specified.specified.

6. Test Condition6. Test Condition6.6 General Test Conditions6.6 General Test Conditions

Shall be set to produce most unfavorable result using Shall be set to produce most unfavorable result using only those conditions that are mentioned by the only those conditions that are mentioned by the manufacturer.manufacturer.

For equipment having several controlled circuitsFor equipment having several controlled circuits Each circuit is considered as single item if intended to be used Each circuit is considered as single item if intended to be used

independently.independently. Group of circuit is considered as single item if intended to used Group of circuit is considered as single item if intended to used

simultaneously.simultaneously.

For control system regulating part of a load only, the For control system regulating part of a load only, the voltage fluctuation produced by each variable part of the voltage fluctuation produced by each variable part of the load alone shall be considered.load alone shall be considered.

5. Limits5. Limits

Applicable at supply terminal of EUT.Applicable at supply terminal of EUT.

Limits:Limits: The value of PThe value of Pstst shall not be greater than 1.0 shall not be greater than 1.0 The value of PThe value of Pltlt shall not be greater than 0.65 shall not be greater than 0.65 The relative steady-state voltage change, dThe relative steady-state voltage change, dcc, shall not , shall not

exceed 3%.exceed 3%. The max. relative voltage change, dThe max. relative voltage change, dmaxmax, shall not exce, shall not exce

ed 4%ed 4% The value of d(t) during a voltage change shall not exThe value of d(t) during a voltage change shall not ex

ceed 3% for more than 200ms.ceed 3% for more than 200ms.

The limits do not apply to emergency switching oThe limits do not apply to emergency switching or emergency interruptions.r emergency interruptions.

Annex AAnnex AApplication of limits and type test conditions for specific Application of limits and type test conditions for specific

equipmentequipment

A.1 Test conditions for cookersA.1 Test conditions for cookersA.2 Test conditions for lighting equipmentsA.2 Test conditions for lighting equipmentsA.3 Test conditions for washing machineA.3 Test conditions for washing machineA.4 Test conditions for tumbler dryersA.4 Test conditions for tumbler dryersA.5 Test conditions for refrigeratorsA.5 Test conditions for refrigeratorsA.6 Test conditions for copying machines, laser printers and similar A.6 Test conditions for copying machines, laser printers and similar appliancesappliancesA.7 Test conditions for vacuum cleanersA.7 Test conditions for vacuum cleanersA.8 Test conditions for food mixersA.8 Test conditions for food mixersA.9 Test conditions for portable toolsA.9 Test conditions for portable toolsA.10 Test conditions for hairdryersA.10 Test conditions for hairdryersA.11 Test conditions for consumer electronic productsA.11 Test conditions for consumer electronic productsA.12 Test conditions for direct water heatersA.12 Test conditions for direct water heaters


equipmentequipment

A.2 Test conditions for lighting equipmentA.2 Test conditions for lighting equipment PPstst and P and Pltlt are only evaluated for lighting equip are only evaluated for lighting equip

ment which is likely produce flicker, for exampment which is likely produce flicker, for example, disco lightingle, disco lighting


equipmentequipment

A.9 Test conditions for portable toolsA.9 Test conditions for portable tools PPltlt shall not be evaluated. shall not be evaluated.

PPstst

Shall be evaluated only when that tool comes with Shall be evaluated only when that tool comes with heating elements.heating elements.

Operate continuously for 10mins or until it switch ofOperate continuously for 10mins or until it switch off automatically.f automatically.


equipmentequipment

A.11 Test conditions for consumer electroA.11 Test conditions for consumer electronic productsnic products For consumer electronics products, only the mFor consumer electronics products, only the m

easurement of deasurement of dmaxmax is required. is required.

ENDEND

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Part 3 Limits- Section 3 : Limition of voltage fluctuations and flicker In low-voltage supply systems for equipment with rated current

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