WO2000079292A1 - Method and device for measuring an electrical equipment discharge - Google Patents
Method and device for measuring an electrical equipment discharge Download PDFInfo
- Publication number
- WO2000079292A1 WO2000079292A1 PCT/FR2000/001701 FR0001701W WO0079292A1 WO 2000079292 A1 WO2000079292 A1 WO 2000079292A1 FR 0001701 W FR0001701 W FR 0001701W WO 0079292 A1 WO0079292 A1 WO 0079292A1
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- WO
- WIPO (PCT)
- Prior art keywords
- voltage
- discharge
- measuring
- electrical equipment
- cut
- Prior art date
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
Definitions
- the present invention relates to a method and a device for measuring the discharge of electrical equipment. This method and this device make it possible, in particular to verify that an electrical equipment complies with low voltage safety standards on the safety of electrical or electronic equipment.
- This standard provides that electrical equipment must not present a risk of electric shock to an operator when this equipment is disconnected from the supply network. This risk of electric shock is caused by the presence in electrical equipment of capacitors which, when disconnected, discharge and therefore generate a voltage across the equipment.
- the standard stipulates that, to be compliant, the attenuation of discharge voltage of electrical equipment must be lowered by 37% in a time interval determined according to the type of device. According to the prior art, the verification of the conformity of an equipment
- the cut does not occur systematically in the most unfavorable cases, that is to say during a positive or negative maximum voltage of the sinusoid of the mains supply network. Therefore, it is necessary to carry out many tests to ensure that the worst case has been reached. Restoring power after disconnection in some cases requires resetting the equipment. In addition, the measurement is carried out directly on the potential of the supply network, which requires the intervention of an authorized operator in order to avoid any risk of accident.
- the object of the present invention is therefore to overcome the drawbacks of the prior art by first proposing a method for measuring the discharge of electrical equipment which is precise and safe for the operator.
- This first object is achieved by the fact that the method for measuring the discharge of electrical equipment comprises:
- the step of determining the change to the maximum positive or negative value comprises, a step of detecting the change to the zero value of the voltage of the electrical power network during the change of the voltage from a value negative to a positive value, and a selection of a time delay.
- the supply cut-off step consists in delaying the triggering of the cut-off for the duration of the selected delay from the instant corresponding to the detection of the zero crossing of the voltage.
- the time delay is determined as a function of the frequency of the supply network and as a function of the operator's choice of the alternation on which the measurement is to be carried out.
- a second object of the invention consists in proposing a device for measuring the discharge of electrical equipment which is precise and does not present any risk of use.
- the device for measuring the discharge of electrical equipment comprises means for detecting the maximum positive or negative value of the voltage of the supply network of an electrical equipment to be tested, means for activation of the power cut triggered by the detection means so that the cut occurs when the voltage has reached the maximum positive or negative value, means for measuring the discharge of the equipment when the cut has been caused.
- the means for activating the cut-off, the detection means and the measurement means are electrically isolated from each other and are decoupled from the supply network.
- the means for detecting the maximum value include means intended to detect zero crossings on the positive alternation of the voltage of the supply network.
- the means for detecting the zero crossing of the voltage include means for rectifying the supply network voltage in positive mono-alternation and means making it possible to obtain a determined time delay at the end of which the means for activating the cut-off, the time delay being determined to trigger the means for activating the cut-off, either when the supply network voltage corresponds to the maximum positive value, or when the supply network voltage corresponds to the maximum negative value.
- the device comprises means for selecting the duration of the time delay as a function of the frequency of the supply network of the equipment to be tested, and as a function of the sign of the maximum voltage value for which the user wishes to perform the discharge measurement.
- the device comprises means for displaying the measurement of the discharge of the equipment to be tested.
- the display means comprise an oscilloscope connected to the measurement means and / or a computer comprising a central unit connected to the measurement means and a monitor allowing the display of the signals representative of the discharge of the equipment to be tested coming from means of measurement.
- the means for activating the cut-off comprise, for the phase and the neutral of the supply network, a switch activated by an optocoupler.
- FIG. 1 represents a block diagram of the device according to the invention
- FIG. 2 shows a diagram showing the electrical insulation of the various modules of the device according to the invention.
- FIG. 3 represents a timing diagram produced at the output of the detection means
- FIG. 4 shows an alternative embodiment of the device according to the invention
- FIG. 5 to 8 show an embodiment of the device according to Figure 4, with discrete electronic components.
- a device Before starting the description of the device according to the invention, it should be recalled that the measurement of the discharge of an item of equipment, after a power cut, meets a standard intended to protect people against electric shock.
- the capacitors present in the appliance will discharge and create a voltage across the connection terminals of the apparatus.
- the capacitors are, in particular present in the apparatus at the level of the known supply filter, intended to attenuate the electromagnetic noises emitted on the supply network.
- a device may include one or more capacitors to ensure continuity of supply to the device during micro-cuts in the distribution network.
- the verification of the conformity of a device with respect to standard EN60950 requires the measurement of the discharge of the capacitor or capacitors of a device after a power failure and this, in the most unfavorable case, that is to say when the value of the voltage of the supply network is maximum either in negative value, or in positive value.
- FIG. 1 shows a block diagram of the device according to the invention.
- the device (1) according to the invention is intended to be connected, on the one hand to the electrical distribution network (S), and on the other hand to electrical equipment (2) to be tested.
- the equipment (2) to be tested is electrically supplied through the device (1) according to the invention, as if it were supplied directly by the electrical distribution network (S).
- the device (1) comprises means (10) for detecting the maximum value of the supply network voltage. These detection means (10) make it possible to detect the maximum positive or negative values of the voltage.
- These means (10) are connected directly to the phase (P), neutral (N) and earth (T) terminals of the electrical supply network (S).
- these detection means (10) are connected to cut-off activation means (12) performing, downstream of the detection means (10), the cut-off of the power supply by means of two switches (120 .P, 120.N) mounted respectively on phase (P) and neutral (N) of the power supply.
- the means (12) for activating the cut-off are electrically supplied by a supply circuit (1200) connected to the mains supply network.
- the link (100) between the detection means (10) and the cut-off activation means (12) allows the transmission to the cut-off activation means (12) of control signals synchronized with the detection of the maximum value of the network voltage by the detection means (10).
- the device (1) comprises also means (11) for measuring the discharge current of the equipment (2) to be tested.
- measuring means (11) are connected, on the one hand, in series on the distribution network downstream from the switches (120.P, 20.N) activated by the means (12) for activating the cut-off, and d on the other hand to the supply terminals of the equipment to be tested (2).
- the measuring means (11) can detect and measure the voltage of the current created by the equipment (2) to be tested at the supply terminals.
- the measuring means (11) are electrically supplied by a supply circuit (1112) connected to the mains supply network.
- the means (11) for measuring the device (1) according to the invention can be connected to means for displaying the measurement carried out.
- These display means comprise, for example, an oscilloscope (3) and / or a computer (4) comprising, in particular a central unit and a monitor and / or a display counter (5) giving the time elapsed after a complete discharge equipment capacitors or the time elapsed for the value of the voltage created across the equipment to reach 37% of the maximum voltage value.
- the detection means (10) comprise means (103) for detecting the zero crossing of the network voltage, for example on the positive half-wave, that is to say when the voltage goes from a negative value to a positive value.
- the means for detecting the zero crossing are chosen to detect the zero crossing when the voltage becomes positive.
- the value of the voltage of the supply network describes a sinusoid, therefore, over an oscillation period, the voltage is canceled twice, a first time passing from a negative value to a positive value, corresponding to the positive alternation, and a second time, passing from a positive value to a negative value.
- the determination of the passage, by the maximum positive or negative value of the voltage is carried out by means of a timing circuit (104) set to the value determined time delay T.
- T the time delay
- the means (103) for detecting the passage at zero transmit to the means (12) for activating the cut-off, and after a time delay in the circuit (104) corresponding to a quarter of a period after the detection of the zero crossing on the positive half-wave, a control signal causing the actuation of the switches (120. P 120.N), by means of an electronic relay or switch, or any other equivalent means, to de-energize the equipment to be tested.
- the cut-off activation means (12) receive the signaj, the switches (120.P, 120.N) are kept in the open position.
- the switches (120.P, 120.N) return to the closed position to energize the equipment (2).
- the timing circuit (104) and the means (13) for detecting the zero crossing of the cutoff are electrically supplied by a supply circuit (1040) connected to the mains supply network.
- the detection means (12) comprise means (101) for rectifying the alternating voltage of the supply network in single alternation. Then, the rectified voltage is applied to the input of processing means (102) to obtain a signal applied to an input (1030) of the means (103) for detecting the passage to zero on the positive half-wave.
- the processing means (102) are intended to improve the quality of the signal transmitted to the zero crossing detection means (103).
- the means (103) for detecting the zero crossing receive on another input (1031) a signal representative of the end of the time delay of the circuit (104) to be applied as a function of the voltage value (maximum positive or negative) from which must be measured the discharge of the capacitor (s) of the equipment to be tested (2).
- the device (1) also comprises control means (13) allowing an operator to select, on the one hand the sign of the maximum voltage value for which the measurement is to be made, and on the other hand the frequency of the network. feed. These control means (13) actually consist in selecting a determined value of the time delay (14).
- the value of the time delay (14) selected is 5 ms.
- the means (103) for detecting the zero crossing produce, on an output connected by the link (100) to the means for activating the cut-off (12), the signal triggering the power cut.
- the device (1) comprises a first logic gate (15), for example of the D flip-flop type, receiving on an input connected to the output (100) detection means (103) of the zero crossing, the signal produced by the means (103) for detecting the zero crossing and on another input (150), a signal from selection means (14) such as a cut command, producing a signal when the user wishes to carry out a discharge measurement.
- the cutoff control (14) must be activated to produce a signal, and the means (103) detection of zero crossing also produce the signal defined above.
- the logic gate (15) emits, on an output (151) to which the means (12) for activating the cut-off are connected, a control signal causing the activation of the switches (120. P, 120.N) to trigger the de-energization of the equipment (2) to be tested.
- the selection means may also include a power-up control (14 ').
- This command is activated when the operator wishes to re-energize the equipment.
- the reset command (14 ') sends a signal to an input (151') of a second logic gate (15 '), of flip-flop type D.
- This flip-flop D (15) also receives on another input (100 ') the sign for detecting zero crossings (102), and provides at output (151') a control signal for energizing the equipment to be tested when the two signals are applied to these two entrances.
- This signal is applied to the cut-off activation means (12) to trigger the closing of the switches (120. P, 120.N). So that the first logic gate (15) transmits the activation signal again to the means for activating the cut-off, the cut-off control (14) must be pressed and the means (103) for detection of zero crossing again produce a signal.
- FIG. 3 represents a timing diagram showing the different signals used.
- the abscissa axis represents time and the ordinate axis represents tension.
- the mains supply voltage describes a sinusoid (S).
- This voltage is rectified to obtain, after processing, a square wave signal (C) which is canceled. on the passage (Z) to zero on the positive alternation.
- this signal (C) constitutes a clock synchronized on the zero crossing on the positive half-wave.
- This signal is delivered by the output of the processing means (102, fig. 1).
- this signal is applied to an input (1030, fig. 1) of the means (103, fig. 1) for detecting zero crossings.
- FIG. 2 represents a diagram showing the electrical insulation of the various modules of the device according to the invention.
- the various means (10, 11, 12) of the invention are electrically isolated from each other and from the mains supply network (S).
- the detection of the maximum voltage and the power cut must occur on the phase (P) and neutral (N) cables directly connected to the distribution network (S).
- means (101) transform the supply network from the sector (S) into an AC voltage of lower determined value and not dangerous, by means of an optical or magnetic coupling.
- the detection means (10) carry out the detection on a lower voltage and are isolated from the mains supply network.
- the activation of the switches (120.p, 120.N) of the means (12) for activating the cut-off is carried out by means of relays electrically isolated from the supply network.
- the means (12) for activating the cut-off comprise on the phase (P) and neutral (N) a switch (120. P, 120. N) activated by an optocoupler (123. P, 123. N) or photocoupler.
- An optocoupler includes a light emitting diode and a phototransistor. When the diode lights up, the phototransistor becomes conducting and closes in the supply circuit, the associated switch (120.P, 120.N).
- the diode is supplied by a very low voltage signal, while the phototransistor is mounted on the mains supply circuit. In this mounting example, the diodes are supplied by the signal coming from the output (151, fig. 4) of the logic gate (15, fig.
- the measuring means (1 1) are also electrically isolated from the supply network.
- an isolation amplifier (1 10) which provides a low voltage image of the mains voltage across the equipment to be tested.
- This amplifier (1 10) is composed of two parts (1 100, 1 101) electrically isolated. A first part (1100) is connected to the phase (P) and to the neutral (N) of the equipment to be tested on the distribution network, and the second part (1110) provides an image of the voltage measured across the terminals. equipment.
- the coupling between the parts (1100, 1110) is of the capacitive type.
- the elements of the device (1) according to the invention apart from the switches (120. P, 120.N), are decoupled from the mains supply and are electrically isolated from each other, which isolates the operator from any risk of electric shock with the mains supply network.
- the device can therefore be used by an operator who is not necessarily authorized to work under voltage.
- the method for measuring the discharge of electrical equipment according to the invention therefore comprises:
- - a step of determining the instant of the passage to the maximum positive or negative value of the supply network of the electrical equipment, - a step of cutting off the supply of the equipment synchronized with the passage to the maximum value positive or negative, - And a step of measuring the voltage at the supply terminals of the electrical equipment.
- the step of determining the instant of passage to the maximum value comprises, for example, a step of detecting the passage to zero of the supply voltage when the voltage passes from a negative value to a positive value and a selection time delay.
- the supply cut-off step consists in delaying the triggering of the cut-off for the duration of the selected delay from the instant corresponding to the detection of the zero crossing of the voltage.
- Figures 5 to 8 show an embodiment of the device according to Figure 4, with discrete electronic components.
- the rectification means (101, fig. 5) comprise a diode bridge.
- the rectified voltage processing circuit (102) comprises two differential amplifiers making it possible to obtain a square-wave signal (C) as shown in FIG. 3.
- the timing circuit (104) is produced by circuits comprising a transistor, resistors and a capacity.
- the determination of the passage to the maximum value is carried out is by a timer (in English timer) (103) receiving on the one hand the signal (1030) representative of the detection of the zero crossings coming from the processing circuit (102) and d on the other hand a signal from the timing circuits (104), from which the timer will apply the determined timing.
- the timing selection means include either a manual switch (13) or an interface (13 ') with a computer.
- FIG. 7 shows the mounting of the optocouplers (123.p, 123.N) with the associated switches (120.P, 120.N).
- Figure 8 shows the assembly of the isolation amplifier (1 10).
- the various electronic components of the device respectively include a transformer, for example with magnetic coupling and a rectifier bridge, a regulator and capacitors.
- This description relates to the use of the device for testing purposes, that is to say that the purpose of the device is to make a cut in the most unfavorable case to measure the discharge of the capacitors present in the equipment in order to check the conformity of the equipment.
- Another use of the device consists in integrating the device (1) according to the invention into the system for switching off electrical equipment, in order to ensure that a voluntary power cut occurs only in the case of more favorable, that is to say when the risk of electric shock is minimal. To do this, the device is modified, to cause the power cut, that is to say the activation of the switches (120.
- the cut-off command (14) corresponds to the switch for switching off the electrical equipment.
- the means (103) for detecting the zero crossing will transmit to the first logic gate (15) a detection signal as soon as the supply voltage passes through zero.
- the first logic gate (15) transmits the cut-off command synchronously with the zero crossing of the voltage.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Relating To Insulation (AREA)
Abstract
Description
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Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP00953220A EP1105741A1 (en) | 1999-06-21 | 2000-06-20 | Method and device for measuring an electrical equipment discharge |
JP2001505206A JP2003502673A (en) | 1999-06-21 | 2000-06-20 | Method and apparatus for measuring electrical equipment discharge |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR99/07840 | 1999-06-21 | ||
FR9907840A FR2795178B1 (en) | 1999-06-21 | 1999-06-21 | METHOD AND DEVICE FOR MEASURING ELECTRIC EQUIPMENT DISCHARGE |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2000079292A1 true WO2000079292A1 (en) | 2000-12-28 |
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ID=9547061
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR2000/001701 WO2000079292A1 (en) | 1999-06-21 | 2000-06-20 | Method and device for measuring an electrical equipment discharge |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP1105741A1 (en) |
JP (1) | JP2003502673A (en) |
FR (1) | FR2795178B1 (en) |
WO (1) | WO2000079292A1 (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SU1317559A1 (en) * | 1986-01-02 | 1987-06-15 | Московский энергетический институт | Device for connecting capacitor bank |
US4868505A (en) * | 1988-06-09 | 1989-09-19 | Stahl G J | High voltage impulse wave generator for testing equipment |
-
1999
- 1999-06-21 FR FR9907840A patent/FR2795178B1/en not_active Expired - Lifetime
-
2000
- 2000-06-20 JP JP2001505206A patent/JP2003502673A/en active Pending
- 2000-06-20 EP EP00953220A patent/EP1105741A1/en not_active Withdrawn
- 2000-06-20 WO PCT/FR2000/001701 patent/WO2000079292A1/en not_active Application Discontinuation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SU1317559A1 (en) * | 1986-01-02 | 1987-06-15 | Московский энергетический институт | Device for connecting capacitor bank |
US4868505A (en) * | 1988-06-09 | 1989-09-19 | Stahl G J | High voltage impulse wave generator for testing equipment |
Non-Patent Citations (1)
Title |
---|
DATABASE WPI Week 8803, Derwent World Patents Index; AN 1988-020460, XP002133030 * |
Also Published As
Publication number | Publication date |
---|---|
EP1105741A1 (en) | 2001-06-13 |
JP2003502673A (en) | 2003-01-21 |
FR2795178B1 (en) | 2001-08-10 |
FR2795178A1 (en) | 2000-12-22 |
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