RU2799983C2 - Method and device for control of performance and area of activity of arc fault protection device - Google Patents

Abstract

FIELD: protection of electrical lines.

SUBSTANCE: invention relates to the protection of electrical lines, in particular to monitoring the performance of devices designed to detect and protect against sparks in electrical networks and electrical installations. Essence: the specified parameters of voltage and current signals in the protected circuit are determined, at which the arc-flash protection device (AFPD) registers sparking in the protected circuit, power to the AFPD device is provided from the protected circuit at the AFPD operability control point, signals are generated by the AFPD operability control device voltage and current with parameters corresponding to the specified parameters of the voltage and current signals, the generated current and voltage signals are detected by the AFPD with the detection of the triggering event of the AFPD.

EFFECT: device for monitoring the operability and coverage of the AFPD is configured to receive power from the protected network and contains a voltage and current signal generator configured to generate signals corresponding to the specified parameters of the voltage and current signals in the protected circuit, at which the AFPD registers sparking in the protected circuit.

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Description

The invention relates to the field of protection of electrical lines, in particular to monitoring the performance of devices designed to detect and protect against sparks in electrical networks and electrical installations.

Arc fault protection devices (AFCI; in the English literature the abbreviation AFCI is used, from Arc-Fault Circuit Interrupter) are a relatively new type of protection device for electrical circuits from fire hazardous overheating and ignition caused by various damages and defects in these circuits. AFDDs operate in continuous operation mode and must be constantly in a state of full functional readiness. Confirmation of this readiness according to the GOST IEC 62606-2016 standard is carried out by a “monitoring function triggered manually and / or automatically to check the arc detection circuit” (clause 8.17 of the standard), the implementation of which is an internal operation of the device itself. At the same time, firstly, there is obviously no guarantee that the control function itself is working. Secondly, most AFDD manufacturers do not provide any data on the method of this control, which makes it impossible to assess the degree of its usefulness or sufficiency. Further, such a self-test does not provide any data on the state of the electrical circuit between the AFDD and the connection points of electrical receivers (electricity consumers of the protected circuit). Therefore, in order to reliably confirm the functional readiness of the AFDD and the circuit protected by it, it is necessary to use a control tool that exerts an external influence on the checked AFDD by applying an influence, preferably from the points of connection of power receivers.

Such devices are available from a number of non-AFCI manufacturers under the general name AFCI Tester, or AFCI tester (hereinafter also referred to as "tester"). Such testers are, for example, the Suretest Circuit Analyzer 61-165 from IDEAL Electrical (available online at https://www.protoolreviews.com/trades/electrical-trades/ideal-suretest-digital-analyzer-61-165/951/), the RT310 from Klein Tools (available online at https://www.kleintools.com/catalog/electrical-testers/ afci-gfci-outlet-tester), Extech CT80 (available online at http://www.extech.com/products/CT80). Any of them can be taken as a prototype of the claimed invention.

These well-known devices have a number of properties that prevent their effective and widespread use in the mass introduction of AFDD, the main of which are as follows.

All known AFDD testers are multi-purpose devices that measure a wide range of various parameters of the electrical circuit. Therefore, they have numerous controls and indications and operation manuals that are difficult for the mass consumer. Many of the functions performed by these testers leads to a high cost of the device. Due to the different ways in which the arc is recognized by different AFDDs, AFDD testers, as noted, among other things, by experts in the field of technology (see, for example, the Internet link https://www.nachi.org/afci-testers-indicators.htm), do not guarantee the operation of a particular AFDD and therefore are considered only as an auxiliary means of monitoring the performance of the AFDD.

Finally, AFDD testers are not intended to and do not evaluate the area of effective operation of an AFDD in the network of its particular installation. This concept means a set of connection points for electrical receivers, in which an arc fault with the lowest spark current, provided for by the GOST IEC 62606-2016 standard, is recognized by the AFDD installed in this circuit. The standard provides for the requirements for the operation of the AFDD with a certain set of loads and extensions in the circuit, but the real circuit may also have significantly greater attenuation of signals in different frequency ranges when they pass from the breakdown point to the AFDD, as a result of which it may not work.

A set of arc fault generators defined by the GOST IEC 62606-2016 standard can serve as a universal means of monitoring the performance and coverage of the AFDD. The generator with a cable sample reproduces the breakdown process along the carbonized section of the insulation, and the generator with electrodes reproduces the breakdown in the gap formed between the conductors. However, such a device is too large, expensive and costly in terms of consumables and laboriousness in operation to serve the mass consumer.

The optimal solution for the tester could be an AFDD control device, made according to the following principles:

1) the device must generate only the signals necessary and sufficient for triggering the AFDD with a given, specific arc fault recognition algorithm. This will drastically reduce the size and cost of the product. It does not matter whether this monitoring device will trigger another type of AFDD;

2) the control device is powered from the control point in which it is connected;

3) when developing a control device, the amplitude of the signals generated by it must be set equal, according to the triggering criterion of the AFDD of this type, to the amplitude of the signals generated by an arc fault with the lowest sparking current, provided for by the GOST IEC 62606-2016 standard. This is achieved by using an attenuator (eg a cable of a certain length) between the AFDD and the arc generator. First, the limiting cable length is determined, at which the reliable operation of the AFDD from the arc generator is maintained, then, at this cable length, the boundary value of the intensity of its signals for the AFDD operation is selected and incorporated into the design of the monitoring device. Since the maximum cable length for operation from arc generators with a cable sample and with electrodes can be different, the smallest of the two value of this length is selected.

Thus, there is a task to create an AFDD control device that would be simple and convenient in operation, have a compact size and provide the ability to assess the effective area of the AFDD in the network of its particular installation.

The technical result of the claimed invention is the expansion of the arsenal of AFDD control devices with giving them new functionality, such as control of the AFDD coverage area, simplifying the design of the device and reducing its dimensions.

The problem is solved, and the claimed technical result is achieved in the proposed method for monitoring the operability of the AFDD and the coverage area of the AFDD (hereinafter, for brevity, also the “control method”), in which voltage and current signals in the protected circuit are measured to determine the sparking event by means of the AFDD. To do this, the method includes determining the specified parameters of voltage and current signals in the protected circuit, at which the AFDD registers sparking in the protected circuit; providing power from the protected circuit at the point of control of the operability of the AFDD; generating voltage and current signals with parameters corresponding to said predetermined voltage and current signal parameters; and detecting said generated current and voltage signals by the AFDD to determine an actuation event of the AFDD.

The task is to be solved, and the declared technical result is also achieved in another object of the present invention - the UZDP operability control device and the UZDP operation zone (hereinafter also the “control device” for brevity), which implements the specified method of monitoring the operability of UZZDP and the UZDP -containing zone of voltage signals and current, made with the possibility of generating the specified signals corresponding to the specified voltage parameters and tok In the protected chain, in which UZDP records sparking in the protected chain.

The essence of the claimed control method and control device lies in the fact that the control device generates only those signals that are necessary and sufficient for triggering the AFDD with the arc fault recognition algorithm specified in it. In this case, the control device is powered from the control point where it is connected, and the amplitude of the signals generated by the control device is set equal to the amplitude of the signals generated by the arc fault according to the triggering criterion of the AFDD of this particular type. At the same time, it is preferable if the determination of the specified specified parameters of the voltage and current signals is performed for the lowest spark current recorded by the AFDD, in particular, with the lowest spark current provided by the GOST IEC 62606-2016 standard.

According to the present invention, the implementation of the control device and the implementation of the control method by it limits their use for a specific type of AFDD with the algorithm for registering the event of sparking and subsequent operation specified in this AFDD, which greatly simplifies the design of the control device and the method of its operation, increases its reliability, and in addition, allows you to control the coverage area of the AFDD by powering the control device from the control point in which it is included.

The invention will now be explained in more detail with reference to the appended figures, where:

in fig. 1 shows a diagram of the inclusion of the claimed control device to check the operability and coverage area of the checked AFDD;

in fig. 2 shows the connection diagram of the claimed control device for determining the shape of the current pulses generated by the control device;

in fig. 3 shows a voltage waveform corresponding to the shape of the current pulses generated by the control device.

The description of the claimed control device and the method of its operation is given on the example of its use with an AFDD according to the patent of the Russian Federation No.

So, for a detailed description of the implementation example of the present invention, it is assumed that the claimed device for monitoring the operability of the AFDD and the coverage area of the AFDD is intended to check the AFDD, the operation algorithm of which is described in the RF patent No. 2660285 and thus is known in advance and taken into account in the design and operation algorithm of the control device.

The control device is included in the circuit as shown in Fig. 1, so that the control device 1 is powered from the controlled network at the operability control point of the AFDD 2.

Further, the control device 1 generates voltage and current signals with parameters corresponding to the parameters of the voltage and current signals, at which this type of AFDD 2 registers sparking in the protected circuit.

With regard to the described option, in each period of the mains voltage, the control device 1 generates a current pulse with a duration of about 100 μs. For this, in particular, a pulse of the specified duration is applied to the gate of a high-frequency field-effect transistor, the source of which is connected to one of the current-carrying wires of the network, and the drain is connected to another wire of the network through a high-precision resistor. The steepness of the leading edge and the pulse duration are sufficient to recognize the signs of an arc fault according to the criteria of the above algorithm. Pulses are generated in positive half-cycles of the mains voltage 1 ms after this voltage passes through zero, which corresponds to a mains voltage of about 100 V.

The waveform of the current pulses can be displayed by the voltage waveform on the current shunt connected in series with the control device 1 in a 230 V network, as shown in FIG. 2. The voltage waveform obtained by means of the oscilloscope 3 and corresponding to the shape of the current pulses generated by the control device 1 is shown in FIG. 3.

Finally, the specified current and voltage signals generated by the control device 1 are detected by means of the tested AFDD 2 with the determination of the triggering event of this AFDD 2.

Thus, the proposed method and device for controlling the AFDD provide the possibility of estimating the effective zone of the AFDD in the network, simplicity and convenience in operation, the device itself has a compact size. As a result of the development, the dimensions and cost of the control device made it possible to include it in the delivery set of each AFDD.

Claims (7)

1. A method for monitoring the operability of an arc fault protection device (AFPD), which determines the sparking event by measuring voltage and current signals in the protected circuit, and the AFDD coverage area using the AFDD operability monitoring device, the method includes: - determination of the specified parameters of voltage and current signals in the protected circuit, at which the AFDD registers sparking in the protected circuit; - supplying power to the AFDD health monitoring device from the protected circuit at the AFDD operability monitoring point; - generation of voltage and current signals with parameters corresponding to the specified specified parameters of voltage and current signals by the device for monitoring the operability of the AFDD; - detection of the indicated generated current and voltage signals by means of the AFDD with the determination of the actuation event of the AFDD. 2. The method according to claim 1, in which the determination of the specified specified parameters of the voltage and current signals is performed for the smallest spark current recorded by the AFDD. 3. A device for monitoring the operability of the arc fault protection device (AFPD) and the coverage area of the AFDD for implementing the method according to claim 1 or 2, configured to receive power from the protected network and containing a voltage and current signal generator configured to generate the indicated signals corresponding to the specified parameters of the voltage and current signals in the protected circuit, at which the AFDD registers sparking in the protected circuit.

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