CN105448617A - Low voltage circuit breaker - Google Patents

Abstract

In order to interrupt at least one electric circuit, the low-voltage circuit breaker has a tripping input so that at least one electric circuit is interrupted. The triggering input is connected to a disturbance arc detection unit which, when a disturbance arc occurs in at least one circuit, detects the disturbance arc and outputs a triggering signal to its output, which leads to the triggering input of the low-voltage circuit breaker terminal, so that the low-voltage circuit breaker can interrupt at least one circuit.

Description

Low voltage circuit breaker

technical field

The invention relates to a low-voltage circuit breaker.

Background technique

Circuit breakers are special switches designed to switch high currents. The circuit breaker can not only switch the operating current and low overload current, but also switch high overload current or short-circuit current in the event of a fault, in addition to maintaining the fault current for a predetermined time and shutting off safely. There are circuit breakers with different numbers of poles, such as single, double, three or four poles.

From the point of view of being used as a simple switching element, a circuit breaker is used as a protection element in the event of a fault, such as a short circuit, an overcurrent or a ground fault. In this case, a switch refers to a low-voltage switch or a low-voltage circuit breaker, which is generally designed for an operating voltage of up to 1000 volts, a maximum of 2000 volts. For example for AC voltages of up to 1000 Volts or DC voltages of 1500 Volts. Circuit breakers are typically used for currents from 100 amps up to 10,000 amps. Special breakers are used for currents starting from 63 amps or from 125 amps.

Circuit breakers, such as compact circuit breakers or molded case circuit breakers, open circuit breakers or air circuit breakers, are used in different distribution layers of the distribution network, such as main distribution network, sub-distribution power grid etc.

Contents of the invention

The technical problem to be solved by the invention is to improve a low-voltage circuit breaker.

This technical problem is solved by a circuit breaker having the features of the invention.

According to the invention, the low-voltage circuit breaker is expanded with a nuisance arc detection unit, so that the circuit is triggered or shut down even in the event of a nuisance arc occurring in the circuit. The core of the invention here is the integration of the disturbance arc detection unit into the system combination with the circuit breaker. Occurring serial and/or parallel interference arcs can thus be detected and interrupted in conjunction with the compact circuit breaker. This has the advantage that the low-voltage circuit breaker can be extended with other functions.

In building installations, arcing can occur due to insulation failures, damage, broken wires and/or loose contacts. These arcs can cause fires. These arcs are referred to herein as disturbance arcs. Alternatively, it is also called arc fault. That is to say, a disturbance arc detection unit is a unit that detects arcs caused by insulation faults, damage, wire breaks and/or loose contacts. In this case, such an arc can occur as a so-called series arc, ie in a series circuit. In addition, it can also occur as a so-called parallel arc, ie between two conductors of an electrical circuit.

Arcs which occur in particular during normal operation of the circuit, for example as a result of switching processes, are not included in the term disturbance arc. These arcs should not be detected by interfering with the arc detection unit.

Such a disturbance arc detection unit is called an arc fault detection device (ArcFault Detection Device), abbreviated as AFDD in English, and is called an arc fault circuit breaker (ArcFault Circuit Interrupter), abbreviated as AFCI in North America. In addition, the interference arc or fault arc detection unit is also referred to as a fire switch.

Preferred configurations of the invention are given in the dependent claims.

In a preferred embodiment of the invention, the disturbance arc detection unit is implemented as a module that can be added to the low-voltage circuit breaker. This has the particular advantage that it can be used to extend existing circuit breakers with new functions.

In a preferred embodiment of the invention, the disturbance arc detection unit is embodied as a module which can be embedded in the housing of the low-voltage circuit breaker. This has the particular advantage that a disturbance arc module can be installed in the circuit breaker instead of other modules and thus provide new functions.

In a preferred embodiment of the invention, the disturbance arc detection unit is integrated in the housing of the low-voltage circuit breaker. That is, the circuit breaker contains a disturbance arc detection unit. As a result, the circuit breaker has other functions, which are advantageously adapted to market requirements.

In a preferred embodiment of the invention, the fault arc detection unit is coupled to the fault current detection unit. This has the particular advantage that a compact unit can be realized which detects both fault currents and interference arcs, wherein functional blocks can be used jointly.

Description of drawings

Exemplary embodiments of the invention are shown in the drawings and explained in more detail below. in:

Figure 1 shows a schematic diagram of a low-voltage circuit breaker with a disturbing arc module;

Fig. 2 shows a schematic diagram of a low-voltage circuit breaker with an interfering arc and a fault current module;

Figure 3 shows a low-voltage circuit breaker with an integrated interfering arc module.

detailed description

FIG. 1 shows a low-voltage circuit breaker MCCB which is capable of interrupting one circuit or several circuits with electrical conductors N, L1 , L2 , L3 . Contact system K is used for interruption. The low-voltage circuit breaker has a tripping input E. If a trigger signal is applied to this trigger input, the electrical conductors N, L1 , L2 , L3 are interrupted via the contact system K, ie the circuit is broken. This is also known as tripping or tripping a circuit breaker. An output terminal of a disturbance arc detection unit AFD, which can output a trigger signal at an output terminal, is connected to the trigger input E. The false arc detection unit AFD has one or more sensors, for example a first sensor I, a second sensor HF, a control unit MCU and a power supply PS. There may also be a third sensor U, not shown.

The first sensor I is used to determine the current of the circuit. The second sensor HF is used to determine the HF spectrum of the circuit. A third sensor U is used to determine the voltage of the circuit. In a polyphase current system, preferably at least 2 of said 3 sensors are used. The control unit MCU is used to control the interference arc detection unit AFD. It is designed to be able to detect disturbance arcs of electrical circuits or disturbance arcs on electrical lines. Interference arcs can be detected, for example, in a circuit with electrical lines N, L1 , L2 , L3 fed by the low-voltage circuit breaker MCCB. If such a disturbance arc is detected and recognized in the circuit, the disturbance arc detection unit AFD outputs a corresponding signal or trigger signal at its output A, which is received by the low-voltage circuit breaker MCCB at its input E and then by means of the contact system K interrupts the circuit. The disturbance arc detection unit can be designed according to FIG. 1 as a disturbance arc module, which is connected to the circuit breaker MCCB via electrical lines. Optionally, it can also be configured that the disturbance arc detection unit can be added to the circuit breaker MCCB.

The arrangement shown in FIG. 2 differs from FIG. 1 in that the fault arc detection unit AFD comprises a fault current detection unit or a fault current module RCD. For example a combination of a fault current detection unit and a disturbance arc detection unit. This means that with the module RCD/AFD both fault currents and interfering arcs can be detected. When one of them is present, the corresponding signal/triggering signal is output to the low-voltage circuit breaker MCCB, which interrupts the circuit if the triggering signal is applied. In the example of FIG. 2 , a disturbance arc detection unit AFD or a disturbance arc and fault current detection unit RCD/AFD can be added to the circuit breaker MCCB.

The arrangement shown in FIG. 3 differs from FIG. 1 in that the disturbance arc detection unit AFD is integrated in the low-voltage circuit breaker MCCB. Alternatively, the integrated disturbance arc detection unit can be detached so that it can optionally be embedded in the circuit breaker MCCB as required. In another variant, the interference arc detection unit can also be fixedly installed in the circuit breaker MCCB.

The present invention is described again in detail below. Additional modules for different functions are already partly provided for circuit breakers. According to the invention, it is proposed to introduce a disturbance arc detection unit into a system combination with low-voltage circuit breakers. In this way, serial and/or parallel interference arcs can be detected centrally. Optionally, other disturbance arc detection units can be used to detect and identify disturbance arcs and thus shut down the circuit to protect the grid. This can be done, for example, in different main distribution networks and/or sub-distribution networks. In this case, the interference arc detection unit can be arranged in the vicinity of the low-voltage circuit breaker, in the device or integrated in the device, or remotely from the low-voltage circuit breaker. In addition, a fault arc detection unit or arc fault protection module located centrally or superordinately on the main feeder side can have a selectivity with respect to arc fault protection modules in downstream sub-distribution networks. Selectivity refers to the identification or triggering of protection elements in the immediate vicinity of faults. This means that as close as possible to the fault, ie the detected fault arc, the fault should be detected by the protective unit there, ie the disturbance arc detection unit, and the circuit should be interrupted there by means of a corresponding low-voltage circuit breaker. As a result, the centrally located or superordinated arc fault protection modules should not be triggered when a disturbance arc occurs in the sub-distribution network. This selective protection can be called basic protection and additional protection.

In addition, the interference arc detection module can be integrated and integrated into the system combination, for example via a bus connection. In a system combination, for example, the data of the low-voltage circuit breaker and the data of the fault arc detection unit can be transmitted or transferred to the monitor. In this case, the interference arc detection unit and/or the low-voltage circuit breaker are connected to a monitor, for example to a central computer. Information about the trigger can be displayed or notified here. In addition, operating parameters can be displayed. Remote triggering is also possible, for example.

The interference arc detection unit can:

a) Constructed as an independent modular functional module;

b) Integrate into other units as a functional module, for example, into a fault current identification unit;

c) directly integrated into the low-voltage circuit breaker as a functional module;

d) As an expansion module of the low-voltage circuit breaker, it is realized in the form of a plug-in module.

In a system combination, the display can be performed equally before or after the detection of a disturbance arc by means of light-emitting diodes, displays, control and notification lines. In addition, measured values and diagnostic process data can be displayed. The connection of the low-voltage circuit breaker, the interference arc module and/or the monitor can take place via cables, eg triggering and remote triggering lines, notification inputs or outputs.

In a further configuration of the invention, the interference arc module can be connected to an electronic tripping unit or an electronic tripping unit of the low-voltage circuit breaker.

Claims (17)

1. A low-voltage circuit breaker for interrupting at least one circuit, having a trigger input, by means of which the low-voltage circuit breaker can be triggered to interrupt at least one circuit, characterized in that the trigger input is connected to A disturbance arc detection unit is connected, which detects a disturbance arc when a disturbance arc occurs in at least one circuit and outputs a trigger signal to its output, which leads to the trigger input of the low-voltage circuit breaker terminal, thereby causing the low voltage circuit breaker to interrupt the at least one circuit. 2. The low-voltage circuit breaker as claimed in claim 1, characterized in that the disturbance arc detection unit is implemented as a module which can be added to the low-voltage circuit breaker. 3. The low-voltage circuit breaker as claimed in claim 1 or 2, characterized in that the disturbance arc detection unit is embodied as a module which can be embedded in the housing of the low-voltage circuit breaker. 4. The low-voltage circuit breaker as claimed in claim 1, characterized in that the disturbance arc detection unit is integrated into the housing of the low-voltage circuit breaker. 5. The low-voltage circuit breaker according to any one of the preceding claims, characterized in that the disturbance arc detection unit is connected to the low-voltage circuit breaker via a wire. 6. The low-voltage circuit breaker as claimed in claim 1, characterized in that the disturbance arc detection unit is coupled to a fault current detection unit. 7. The low-voltage circuit breaker as claimed in claim 1, characterized in that the disturbance arc detection unit has a control unit, a first sensor for determining the current and a high-frequency spectrum for determining at least one circuit the second sensor. 8. The low-voltage circuit breaker as claimed in claim 7, characterized in that the disturbance arc detection unit has a third sensor for determining the voltage of at least one circuit. 9. The low-voltage circuit breaker as claimed in claim 7 or 8, characterized in that the first sensor determines the current and the high-frequency spectrum of at least one circuit. 10. The low-voltage circuit breaker according to any one of the preceding claims, characterized in that each phase of a multi-phase current system is provided with said sensor. 11. The low-voltage circuit breaker as claimed in claim 1, characterized in that the interference arc detection unit is selective with respect to other interference arc detection units. 12. The low-voltage circuit breaker as claimed in claim 1, characterized in that the disturbance arc detection unit has a power supply. 13. The low-voltage circuit breaker as claimed in claim 7, characterized in that the control unit has a microprocessor. 14. The low-voltage circuit breaker as claimed in claim 1, characterized in that the disturbance arc detection unit has a communication unit which can be connected to a communication branch for data exchange. 15. The low-voltage circuit breaker as claimed in claim 14, characterized in that the disturbance arc detection unit is designed such that triggering data, diagnostic data, process data and/or control data can be transmitted and/or exchanged by means of the communication unit data. 16. The low-voltage circuit breaker as claimed in claim 1, characterized in that the disturbance arc detection unit has a display unit. 17. The low-voltage circuit breaker as claimed in claim 16, characterized in that the display unit has a display and/or light-emitting diodes for displaying the operating state of the disturbance arc detection unit.