SK812009U1 - Device for automatically detecting continuity of the protective earth conductors pe and pen - Google Patents

Abstract

Technical solution concerns an equipment for an automated measurement of the continuity of the PEN conductor and a protective conductor PE in regards with a STN 33 2000-6. The described technical solution considers two equipments. The first one (PENCE) is designed to automatically measure the continuity of the PEN conductor from the source {a transformer} up to a point of distribution of the PEN conductor. It is done through a transformer, which measures the current (MTP). Second, an additional equipment,(ENCE), automatically measures the continuity of the protective conductor PE from the PEN conductor's point of distribution in the switchbox up to the final current-using equipment in the electrical installations. This is done in the supply net TNC-S. Using these equipments (PENCE) and (ENCE) at the same time safeguards the control of the continuity of the PEN conductor and protective conductor from the source of electric energy, the transformer, up to the current-using equipment.

Description

The described technical solution consists of two devices. The first PENCE device is designed to automatically detect the continuity of a PEN protective conductor in a power distribution network that is a dedicated technical electrical device, from a source i.e. from the transformer to the dividing point of the PEN conductor into a separate N conductor and a separate PE conductor in the switchgear in the TNC resp. TNC-S. The second additional ENCE device automatically detects the continuity of the PE protective conductor from the point of distribution of the PEN conductor in the switchgear to the end consumer in the electrical installations, TNC-S network, or the network. TNS, especially in socket circuits, and in circuits of objects L / first / class. The simultaneous use of the PENCE and ENCE devices thus covers the control of the continuity of the protective conductor from the power source, i.e. from transformer to appliance.

Note: Class I articles are electrical articles for which a protective terminal is prescribed and for which a protective conductor is used to protect against electric shock.

BACKGROUND OF THE INVENTION

At present, we are not aware of a device that would automatically measure the continuity of a PEN and PE protective conductor.

In accordance with IEC 60364-6: 2006 and the harmonization document HD 60364-6, the harmonized STN 33 2000-6 Part 6: Revision referred to in Art.

61.3.2 (joint modification with international standard) - Continuity of conductors in paragraph (a) Continuity test shall be carried out on protective conductors, including protective conductor conductors and supplementary conductor conductors. The inspection technician can verify the continuity of the PEN and PE protective conductor, e.g. by measuring impedance / resistance / protective conductor with special conductor resistance meters, resp. which is technically demanding, sometimes impossible for long distances.

Inspections of electrical equipment are carried out when the equipment is put into operation / initial revision resp. initial inspection and / or examination repeatedly in the prescribed terms depending on the type of object in which the wiring is located and depending on external influences ranging from / 2 to 5 years. In the period before the required initial revision eg.

after assembly, repair, reconstruction, modernization and between repeated revisions, the PEN or PE protective conductor may be interrupted and a dangerous condition in the electrical installation, i.e. to the possibility of electric shock.

/ There have been instances where electrical equipment has been destroyed when the protective conductor has been interrupted or, in the worst case, fatal injury.

The essence of the technical solution

The risk of electric shock when the protective conductor is interrupted is increased because the electrical equipment may be capable of operating, but the most widespread protection against electric shock to inanimate parts by self-disconnection from the power supply is not effective.

In particular, these are objects where electrical energy (wiring) is used by persons without electrical qualifications, laymen, and thus there is an increased likelihood of electric shock.

If the PEN or PE protective conductor is interrupted, there is no protection against electric shock by self-disconnection from the power supply, and the functions of supplementary protection against electric shock - residual current circuit breakers and overvoltage protections are also endangered.

The present technical solution of the ENCE and PENCE devices see. chickens. 4 are devices containing electrical and electronic components contained in individual parts of the devices. ENCE device see. chickens. No. 1 includes power supply units NZE, pulse generator GIE, v measurement blocks MBE, control unit RJE and signaling unit SJE, and in the PENCE device see. chickens. 3, protection block BI, rectifier U, power supply NZ, backup power supply A, measuring circuits MO, auxiliary circuits of current transformer POMTP, current transformer MTP, control unit RJ and signaling unit SJ

The use of this technical solution is designed for the automatic detection of the continuity of the protective conductor PEN / PENCE device / and PE / ENCE device / in the TN-C-S network. TNS, in switchboards and electrical circuits located in the power distribution. In this case, automatically detecting the continuity of the protective conductor means that it is possible to set the time how often the continuity of the protective conductor is to be checked / e.g. once per minute, hour, 24 hours and so on / depending on the duration of use of mainly Class I items.

The ENCE is comprised of an NZE power supply including a back-up battery - autonomous as needed /, a GIE pulse generator, two MBE1 and MBE2 measuring blocks, an RJE control unit mainly comprising comparators and a microprocessor, and a SJE signaling unit containing signaling elements. The essence of automatic continuity measurement of PE protective conductor consists in sending pulses according to STN EN 61557 / IEC 61557 / through protective conductor and middle conductor and their identification from which direction the pulses return, by means of current transformers and evaluation of these pulses by microprocessor placed in the control RJE unit. After the pulses are detected and the protective conductor status is evaluated by the microprocessor, the status of the protective conductor and protective connection is signaled by the green LED. In the event of an interruption of the protective connection but an uninterrupted protective conductor, the red LED will be permanently lit and a continuous, audible beep will sound to indicate an imminent dangerous condition; operator / user / electrical equipment that work with electrical equipment, especially Class I, must not be continued.

The power supply of the ENCE in the three-wire system is single-phase, see. chickens. No. 1, in a five-conductor system it can be single-phase or three-phase see. chickens. No.2. Three-phase power supply increases the reliability of the power supply while checking the interruption of one of the phases.

The "TT" test button is part of the RJE control unit and is used to run the continuity test of the protective conductor and protective bonding at any time, especially when starting to use electrical objects in class

I. e.g. washing machines, etc. After the continuity test, the ENCE shows the user of the electrical object that the device is connected to a protective conductor and can be used safely.

We recommend ensuring the ENCE is protected against overvoltage by class D / IV / overvoltage protection.

We propose to use the ENCE device directly in socket circuits /1.j. directly in the sockets / and especially in the circuits of appliances /1.j. directly in appliances / I. / first / class, such as washing machines, dishwashers, refrigerators, freezers, electric heaters, water heaters and irons in households, refrigerators, freezers in restaurant facilities, office computers, computers and engines in production plants.

The PENCE device includes: NZ power supply, which provides power to the control and auxiliary circuits and to charge the backup battery A. Battery A is continuously recharged during operation and provides power to the control and signaling unit in the event of a power failure or interruption. The autonomy of the power supply of the device given the battery capacity must be determined individually according to the type of operation where the device will be used. However, we recommend at least 6h. The power supply is designed as a galvanic isolated, its primary neutral point is possible to increase safety in case of detected PEN wire interruption via

to disconnect the electronic high impedance switching circuit with a control signal from the control unit.

The phase voltages are rectified in the rectifier U in one way. Positive and negative half-waves are evaluated separately. The measuring resistance divider in the MO at voltage connection (via an electronic switching element) flows the measuring current (according to STN EN 61557, IEC 61557), which generates a voltage drop on the divider, smoothed by the capacitor. This voltage is compared with the reference value in the comparator and the evaluated logic output of this operation is processed by the control unit RJ.

The MTP current transformer must be dimensioned according to the parameters of the switchgear in which it is connected. In the secondary circuit in the POMTP, the measurement transformer, due to the need to evaluate relatively small currents, it is necessary to provide sufficient resolution of the evaluation circuit within the range of values and the current of the PEN continuity itself (under unloaded PEN conductor). At the same time, the circuit must also bear the full load (from the load), while distinguishing the absolute value of the current is only necessary to the extent necessary for evaluating the measuring current. The MTP current transformer is used in the circuit for the purpose of determining the path of the closing of the measuring current from the power supply:

1. PEN conductors to the power supply,

2. to the local ground of the PEN of the driver;

3. PEN conductors.

For proper operation of the device, the MTP should be connected (from the point of view of the power supply - eg transformer) before the point of division and local grounding and connection of this device to the PEN wire.

The control unit RJ ensures connection of the measuring circuit at required intervals, evaluates the measuring current, its closing path and controls the signaling unit in case of PEN disconnection of the conductor and power failure. The control unit also includes a test button "TT", which is used to run the test of continuity of the protective conductor and protective bonding at any time.

The signaling unit SJ signals the safe and fault states by means of a sound and light signaling. In case of an uninterrupted PEN wire, the green LED lights up. If the PEN wire break is evaluated, the red LED flashes and a strong, intermittent intermittent beep sounds. In the event of a power failure, the red LED will light and a continuous beep will sound.

In this case, automatically detecting the continuity of the protective conductor PEN means that it is possible to set the time how often the continuity of the protective conductor is to be checked / e.g. once per minute, hour, 24 hours, etc. / depending on the duration of use of Class I items.

The PENCE device is intended for use in the TNC's low-voltage networks. TNC-S, where it is to perform the task of automatic operational continuous check of continuity of the PEN supply conductor.

There is an increased risk of electric shock in metal distribution and protection cabinets of the electricity distribution network, given the fact that they are placed in publicly accessible places and are accessible to non-electrically qualified persons, laymen. If the PEN protective conductor is interrupted, there is no protection against electric shock by disconnecting itself from the power supply after the PEN conductor interruption point, and phase voltages may be given to the inanimate parts of metal distribution and protection cabinets and class I appliances in the downstream wiring.

We recommend PENCE for use directly in switchgear in order to make available / visible and audible / signaling the protective conductor status. The advantage of using the PENCE in conjunction with the ENCE is that it covers the continuity check of the protective conductor from the transformer source to the appliance. See. chickens. No.4.

Another advantage of using two PENCE and ENCE devices is to divide the continuity measurement of the protective conductor into a part from the source to the split point and the part after the split point. Downstream of the distribution point, PE and N conductor are used for the measurement and thus the transformer is not loaded by the measuring pulses, which could cause problems with a large number of consumers.

Due to the fact that the ENCE and PENCE devices contain electronic components, it has an estimated self-consumption (assuming up to 2 W), which is a disadvantage. Another disadvantage is that it can be a source of higher harmonics, since in this design the device does not include a higher harmonics filter. If the ENCE and PENCE devices are used in larger quantities, we recommend to equip the device with a harmonic filter.

Overview of drawings

Drawing no. 1 - Block diagram of the ENCE device for automatic continuity measurement of PE protective conductor for three-wire electrical installation

Drawing No.2 - Block diagram of the ENCE device for automatic PE continuity measurement for five-wire electrical installation

Drawing 3 - Block diagram of a PENCE device for automatic continuity measurement of a PEN protective conductor

Drawing 4 - Example of connection of ENCE and PENCE devices for automatic continuity measurement of PEN and PE protective conductor

Example of technical solution.

Device for automatic measurement of PE conductor continuity. ENCE see. chickens. No. 1, the device consists of a power supply NZE including a back-up source - accumulator with autonomy as needed eg. 12 hours, GIE pulse generator. two measuring blocks MB1 and MB2 with current transformers, an RJE control unit comprising mainly comparators, a control microprocessor and a test button TT, and an SJE signaling unit comprising a green and a red LED and a piercing sound signaling.

The device is mounted directly into an I. / first / class appliance, eg. washing machines, dishwashers, computers, etc. where it will indicate the status of the PE protective conductor after the dividing point, or directly to the power supply socket

Class I.

Protective wire continuity measurement consists of transmitting pulses from the GIE pulse generator via the protective conductor and the intermediate conductor, identifying which direction the pulses return from / using current transformers in the MBE1 and MBE2 measuring blocks, and evaluating them via a microprocessor located in the RJE control unit. .

After evaluation of the pulses by the microprocessor, the status of the continuity of the protective conductor and the protective connection is signaled in the signaling unit SJE by the green LED. In the event of an interruption of the protective connection but an uninterrupted protective conductor, the red LED will be on permanently and a continuous, audible beep will sound to indicate an imminent dangerous condition. operator / user / electrical equipment, that electrical equipment must not be touched, and that work with electrical equipment, especially Class I, must not be continued.

At the same time, a device for automatic continuity measurement of the protective conductor PEN, PENCE, which contains NZ power supply, which provides power supply for control and auxiliary circuits and charging of backup battery A, is mounted on the switchboard supply. Battery A is continuously recharged during operation and power failure or interruption The PEN driver provides power to the RJ control unit and the SJ signaling unit. The autonomy of the power supply of the device given the battery capacity must be determined individually according to the type of operation where the device will be used. However, we recommend at least 6h. The power supply NZ is designed as a galvanic isolated, its primary neutral point can be disconnected by a control signal from the control unit RJ to increase safety in case of detected PEN wire break by means of an electronic high impedance switching circuit.

The way of evaluating PEN continuity of the driver is as follows:

The phase voltages are rectified in the rectifier U in one way. Positive and negative half-waves are evaluated separately. The MOL MO2 measuring circuit, when connected to a voltage (via an electronic switching element), flows the measuring current (in accordance with SIN EN 61557, IEC 61557), which generates a voltage drop on the divider, smoothed by the capacitor. This voltage is compared with the reference value in the comparator and the evaluated logic output of this operation is processed by the control unit RJ.

The MTP current transformer must be dimensioned according to the parameters of the switchgear in which it is connected. In the secondary circuit in the POMTP, the measurement transformer, due to the need to evaluate relatively small currents, it is necessary to ensure sufficient resolution of the evaluation circuit within the range of the values of the PEN conductor continuity measurement itself (with the PEN conductor unloaded). At the same time, it is necessary for the circuit to withstand the full load (from the load), while distinguishing the absolute value of the current is only necessary to the extent necessary for evaluating the measuring current. The MTP current transformer is used in the circuit for the purpose of determining the path of the closing of the measuring current from the power supply:

1. PEN conductors to the power supply,

2. to the local ground of the PEN of the driver;

3. PEN conductors.

For proper operation of the device, the MTP should be connected (from the point of view of the power supply - eg transformer) before the point of division and local grounding and connection of this device to the PEN wire.

The control unit RJ ensures connection of the measuring circuit at required intervals, evaluates the measuring current, its closing path and controls the signaling unit in case of PEN disconnection of the conductor and power failure. The RJ control unit also includes a test button TT, which is used to run the continuity test of the protective conductor and the protective connection at any time.

The signaling unit SJ signals the safe and fault states by means of a sound and light signaling. In case of an uninterrupted PEN wire, the green LED lights up. If the PEN wire break is evaluated, the Red LED flashes and a strong, intermittent intermittent beep sounds. In the event of a power failure, the red LED will light and a continuous beep will sound.

Claims (2)

1. The protective conductor continuity measuring device (IPE) (IPE) is characterized in that the automatic conductor continuity measuring device (PE) after the distribution point (ENCE) comprises a power supply (NZE) with a back-up battery single-phase wiring supplying the pulse generator (GIE), which is connected to the conductor (N) and the measured conductor (PE) and the control unit (RJE), the power supply unit (NZE) is the source of the measuring block voltage (MBE1) and (MBE2) ) and a control unit (RJE) equipped with a test button (TT), outputs from the measuring blocks (MBE1) and (MBE2) are led to a control unit (RJE) and the control unit is connected to a signaling unit (SJE) of the device (ENCE) ), and a device (PENCE) for measuring the continuity of the protective conductor (PEN) before the split point, which consists of a block of protection (BI) connected to the The block (BI) is connected to a power supply unit (NZ) which is three-phase and supplies a backup battery (A) and a control unit (RJ), which is equipped with a test button (TT) and which is connected with measuring circuits (MO1) and (MO2) connected from the rectifier (U), the control unit (RJ) also being connected to the auxiliary circuits (POMTP) of the current transformer (MTP) and also connected to the signaling unit (SJ) which is, like the control unit (RJ), connected to the backup battery (A). Device according to claim 1, characterized in that in a five-wire electrical installation, the power supply (NZE) is single-phase or three-phase.