JP5388879B2 - Uninterruptible testing device and uninterruptible testing method for circuit breaker for wiring - Google Patents

Description

  The present invention relates to an uninterruptible testing apparatus and an uninterruptible testing method for a circuit breaker for performing an overcurrent breaking function test of a circuit breaker installed between an electric wire and a load.

  A circuit breaker for wiring (MCCB: Molded Case Circuit Breaker, NFB: No Fuse Breaker, etc.) is installed between the electric wire and the load, and breaks the circuit when an abnormal current flows to the load side due to a short circuit etc. This protects the load and electric wires from damage. In order to determine whether or not the breaking function of this circuit breaker is normal, it is necessary to perform an overcurrent breaking function test. The overcurrent cutoff function test applies a large current to the main circuit of the circuit breaker for wiring, so in order to protect loads such as electrical equipment connected to the circuit breaker for wiring from damage such as damage, It is necessary to disconnect the load connected to the circuit breaker and use a dedicated test device (see, for example, Patent Document 1).

JP 2008-271682 A

  However, when the load connected to the circuit breaker is disconnected or attached in order to perform the above test, it is necessary to power out the entire circuit on the load side. For this reason, the overcurrent cutoff function test of the circuit breaker for wiring used for a circuit where a power failure is difficult such as a disaster prevention facility is in a difficult situation. As a result, it becomes difficult to grasp the deterioration state of the breaking characteristics of the circuit breaker for wiring, and when the breaking characteristics are deteriorated, such a circuit breaker is continuously used. There is a risk that.

  In addition, even if the over-current breaker function test of the circuit breaker can be performed with the circuit breaker connected to the main circuit, if the circuit breaker is interrupted by the test current, The entire circuit on the load side connected to the circuit breaker fails.

  Therefore, the present invention provides an uninterruptible testing apparatus and an uninterruptible testing method for a circuit breaker capable of performing an overcurrent breaking function test in a state in which supply of load current to a load connected to the circuit breaker is maintained. The purpose is to provide.

  In order to solve the above-mentioned problem, the invention of claim 1 is an uninterruptible testing apparatus for performing an overcurrent cutoff function test of a circuit breaker installed between an electric wire and a load, A test power supply means for supplying a test current to the circuit breaker; a voltage detection means for detecting a voltage by the test power supply means; and when the voltage detected by the voltage detection means exceeds a predetermined voltage, the test power supply means Power disconnecting means for interrupting, switching means for switching connection between the circuit breaker for wiring and the test power supply means, and connection to the circuit breaker for wiring when the circuit breaker for wiring is interrupted by the test current And bypass means for supplying a load current from the electric wire to the loaded load.

  The invention of claim 2 is an uninterruptible test method for performing an overcurrent cutoff function test of a circuit breaker installed between a wire and a load, supplying a test current to the circuit breaker, When the circuit breaker is cut off by the test current, the load current is bypassed and supplied from the electric wire to the load connected to the wiring circuit breaker, and the voltage generated by the flow of the test current exceeds a predetermined value The test current supply is cut off.

  According to these inventions, an overcurrent cutoff function test of a circuit breaker connected to a load is performed, and when the circuit breaker operates and the load side circuit is interrupted, the circuit breaker is connected to the circuit breaker. The load current is bypass-supplied from the electric wire to the generated load.

  According to the first and second aspects of the present invention, when a voltage of a predetermined value or more is detected in the circuit through which the test current flows, the supply of the test current is cut off, so that the circuit is connected to the circuit breaker for wiring. There is no risk of large current flowing through the load. For this reason, the load connected to the circuit breaker for wiring is not likely to be damaged, so the overcurrent blocking function test of the circuit breaker for wiring should be performed without removing the load connected to the circuit breaker for wiring. Can do.

  Also, even if the breaker for wiring operates and breaks during the overcurrent breaker function test, the load will be cut off because the load current is bypassed from the wire to the load connected to the breaker for wiring. There is nothing. This eliminates the need for power failure measures associated with the overcurrent interrupt function test of the circuit breaker for wiring, and interrupts for wiring used in important circuits that are difficult to perform power outages such as electrical circuits that supply power to disaster prevention facilities. The overcurrent cutoff function test can be easily performed on the tester.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the uninterruptible testing apparatus of the circuit breaker for wiring which concerns on embodiment of this invention. It is a circuit diagram which shows the initial state of the overcurrent interruption | blocking function test of the positive electrode side in the uninterruptible testing apparatus of FIG. It is a circuit diagram which shows the state at the time of the positive electrode side of the circuit breaker for wiring in the overcurrent interruption | blocking function test following the state of FIG. 2 interrupting | blocking previously. It is a circuit diagram which shows the state at the time of the circuit breaker for wiring in the overcurrent interruption | blocking function test following the state of FIG. 3 having completely interrupted | blocked. FIG. 5 is a circuit diagram illustrating a test current interruption state in an overcurrent interruption function test following the state of FIG. 4. It is a circuit diagram which shows the initial state of the overcurrent interruption | blocking function test of the negative electrode side in the uninterruptible testing apparatus of FIG.

  The present invention will be described below based on the illustrated embodiments.

  FIG. 1 is a schematic configuration diagram of an uninterruptible testing apparatus 1 for a circuit breaker according to this embodiment, and FIGS. 2 to 6 are diagrams showing a test method by the uninterruptible testing apparatus 1.

  The uninterruptible testing device 1 is a device that performs an overcurrent cutoff function test of the circuit breaker 2 installed between the distribution line (electric wire) PL and the load 3, and is mainly a low voltage that supplies the test current dt. A large current insulated power supply (test power supply means) 11, a voltage detection means 12 for detecting the voltage of the low voltage large current insulated power supply 11, and a low voltage large current insulated type when a voltage exceeding a predetermined value is detected. Power supply cutoff means 13 for cutting off the power supply 11, switching means 14 for switching the connection between the test electrode (positive electrode and negative electrode) of the circuit breaker 2 and the low-voltage high-current insulated power supply 11, and load current from the distribution line PL and a bypass circuit (bypass means) 15 for supplying d to the load 3. Here, in this embodiment, 5 A is assumed as the rated current of the circuit breaker 2 for wiring, and 50 mΩ is assumed as the contact impedance, for example.

  The uninterruptible testing apparatus 1 is connected to a commercial power source (power supply source) via power terminals T1 and T2, and power from the commercial power source is supplied to a low-voltage high-current insulated power source 11 via a first switch CB1. It comes to be supplied. The low-voltage, high-current insulated power supply 11 converts power from a commercial power supply into a voltage and current suitable for an overcurrent interruption function test, and outputs a test current dt. In this embodiment, for example, It is assumed that the rated voltage is about 5V or less and the rated current is about 100A. Further, a reverse current prevention circuit for the device 1 is provided.

  Such a low-voltage, large-current insulated power source 11 is connected to the switching means 14 via the second switch CB2 and the third switch CB3. In addition, the voltage detection means 12 is connected in parallel with the low-voltage large-current insulated power supply 11 and between the second switch CB2 and the third switch CB3. This voltage detection means 12 is a low resistance element for detecting the voltage of the low voltage large current insulation type power supply 11, and is set to, for example, approximately 1Ω in this embodiment. In this way, the low-voltage, large-current insulated power supply 11, the voltage detection means 12, and the switching means 14 are connected in parallel.

  The power shut-off means 13 is connected in parallel to the voltage detection means 12 and is composed of a conversion circuit (A / D: Analog / Digital) and a microprocessor (MPU: Microprocessor) as an arithmetic unit. When the voltage detecting means 12 detects a voltage of a predetermined value (for example, 3V in the above assumption) or more, the power shutoff means 13 sends a control signal to shut off the switches CB1 to CB3 as will be described later. To be sent.

  The switching unit 14 includes a first changeover switch SW1 and a second changeover switch SW2. By switching the changeover switches SW1 and SW2, the direction of the test current dt, that is, the test circuit can be switched to the positive electrode side or the negative electrode side. It is like that. Specifically, the first changeover switch SW1 includes a positive electrode side terminal SW11 connected to the load side positive electrode terminal P2, a negative electrode side terminal SW12 connected to the electric wire side negative electrode terminal N1, and a neutral terminal SW13. Yes. Similarly, the second changeover switch SW2 includes a positive electrode side terminal SW21 connected to the electric wire side positive electrode terminal P1, a negative electrode side terminal SW22 connected to the load side negative electrode terminal N2, and a neutral terminal SW23.

  Further, a bypass circuit 15 is connected between the switching means 14 and the terminals P1, N1, P2, and N2. That is, the bypass circuit 15 includes a fourth circuit breaker CB4, a positive-side Schottky barrier diode SBDP that allows only a current flow from the wire-side positive terminal P1 side to the load-side positive terminal P2 side, and a load-side negative electrode A negative-side Schottky barrier diode SBDN that allows only a current flow from the terminal N2 side to the electric-wire-side negative terminal N1 side. The wire side positive terminal P1 and the load side positive terminal P2 are connected via the diode SBDP and the fourth circuit breaker CB4, and the wire side negative terminal is connected via the diode SBDN and the fourth circuit breaker CB4. N1 and the load side negative terminal N2 are connected. Here, as the fourth circuit breaker CB4, one that matches the rated breaking capacity of the wiring circuit breaker 2 is selected.

  Next, the operation of the uninterruptible testing apparatus 1 for a circuit breaker having such a configuration and the uninterruptible testing method for a circuit breaker according to this embodiment will be described. First, the overcurrent interruption function test of the positive side contact of the circuit breaker 2 for wiring will be described. Here, it is assumed that the distribution line PL and the circuit breaker 2 for wiring, and the circuit breaker 2 for wiring and the load 3 are connected by the positive electrode side electric wire LP and the negative electrode side electric wire LN.

  First, the load 3 connected to the circuit breaker 2 is stopped as much as possible so that the load current d flowing to the circuit breaker 2 during the overcurrent circuit breaker test is minimized. Next, in a state where all the switches CB1 to CB4 of the uninterruptible testing apparatus 1 are opened, the first changeover switch SW1 and the second changeover switch SW2 of the switching unit 14 are switched to the positive terminal SW11 and SW21. Then, the output of the low-voltage large-current insulated power supply 11 is set to 10A. Next, the electric wire side positive electrode terminal P1 of the test apparatus 1 and the distribution line PL side of the positive electrode side electric wire LP side of the wiring breaker 2 are connected by the test line 4, and the electric wire side negative electrode terminal N1 and the electric circuit breaker 2 are connected. The test wire 4 connects the negative electrode side wire LN side to the distribution line PL side. Similarly, the load side positive terminal P2 of the test apparatus 1 and the load 3 side on the positive side wire LP side of the circuit breaker 2 are connected by the test line 4, and the load side negative terminal N2 and the circuit breaker 2 are connected. The load 3 side on the negative electrode side electric wire LN side is connected by the test line 4.

  In such a state, the first switch CB1 is turned on to charge the low-voltage, high-current insulated power supply 11, and the third switch CB3 and the fourth switch CB4 are turned on. At this time, since the diodes SBDP and SBDN are connected in series to the bypass circuit 15 and the impedance is higher than that of the circuit breaker 2 for wiring, most of the load current d flows to the circuit breaker 2 for wiring.

  Subsequently, as shown in FIG. 2, the second switch CB <b> 2 is turned on, and a test current dt is applied to the positive contact of the circuit breaker 2 for wiring. At this time, in the case of the above-described assumption example, the resistance value of the test circuit is 0, which is a parallel resistance value of 1Ω which is the resistance value of the voltage detecting means 12 and 50 mΩ which is the contact impedance of the circuit breaker 2 for wiring. .0476Ω. For this reason, in order to flow 10 A which is the set electric current, the output voltage of the low voltage large current insulated power supply 11 becomes 0.476V. Further, the voltage applied to both ends of the voltage detection means 12 is 0.476V, which is less than 3V, which is the cutoff voltage set by the MPU of the power cutoff means 13, so that unnecessary breaking operations of the breakers CB1 to CB3 do not occur. Further, the test current dt does not flow to the bypass circuit 15 due to the rectification action of the diodes SBDP and SBDN connected in series to the bypass circuit 15.

  Next, the test current dt (10 A) output from the low-voltage, high-current insulated power supply 11 is approximately 9.5 A (= {1Ω / (1Ω + 0.05Ω)} × 10 A to the positive contact of the circuit breaker 2 for wiring. ) Since it is energized and greatly exceeds the rated current of 5A, the positive contact of the circuit breaker 2 is interrupted as shown in FIG. In this embodiment, an example in which the positive electrode side contact is interrupted in advance will be described. However, the same applies to the case where the negative electrode side contact is interrupted in advance due to a mechanical structure.

  FIG. 3 is a diagram illustrating a point in time when the positive contact of the circuit breaker 2 for wiring is interrupted in advance. At this time, the positive-side load current d flows from the positive-side electric wire LP to the load 3 from the positive-side Schottky barrier diode SBDP via CB4. On the other hand, the negative-side load current d flows from the load 3 through the wiring breaker 2 to the negative-side electric wire LN because the negative-side contact of the wiring breaker 2 is not cut off. In this way, even when the positive electrode side contact of the circuit breaker 2 for wiring is interrupted in advance, the supply of the load current d is maintained. Moreover, if the positive side contact is interrupted in advance, the circuit breaker 2 for wiring will be in an irregular state for a moment, but since the mechanical latch is released, the negative side contact will also be disconnected without taking time, The circuit breaker 2 is completely interrupted.

  After the circuit breaker 2 for wiring is completely cut off, as shown in FIG. 4, the load current d flows from the positive-side electric wire LP to the load 3 via the CB4 from the positive-side Schottky barrier diode SBDP. The load 3 flows from CB4 to the negative electrode side electric wire LN through the negative electrode side Schottky barrier diode SBDN. In this way, even when the circuit breaker 2 for wiring is completely interrupted, the supply of the load current d to the load 3 side is maintained.

  Furthermore, after the circuit breaker 2 for wiring is completely cut off, as shown in FIG. 5, all the current 10A output from the low voltage large current insulated power supply 11 flows through the voltage detecting means 12, and the low voltage Since the voltage related to the large current insulated power supply 11 (the voltage input to the power shut-off means 13) is larger than the cut-off voltage 3V set in the MPU of the power shut-off means 13, the third voltage from the MPU of the power shut-off means 13 is increased. A cut-off signal is output to the switch CB3. Subsequently, after an interruption signal is output from the MPU of the power interruption means 13 to the first switch CB1, an interruption signal is output from the MPU of the power interruption means 13 to the second switch CB2, and the test current dt is energized. Is stopped.

  On the other hand, when the overcurrent interruption function test is performed on the negative electrode side contact of the circuit breaker 2 for wiring, the first changeover switch 14 of the switching means 14 is opened with all the switches CB1 to CB4 being opened. The switch SW1 and the second switch SW2 are switched to the negative terminals SW12 and SW22. Then, an overcurrent interruption function test is performed by the same procedure as that for the positive electrode side (see FIG. 6). FIG. 6 shows an initial state in which the switches CB <b> 1 to CB <b> 4 are sequentially turned on and the test current dt is supplied to the negative contact of the circuit breaker 2 for wiring.

  As described above, according to the uninterruptible testing device 1 and the uninterruptible testing method for the wiring breaker 2, it is possible to perform an overcurrent breaking function test in a state where the wiring breaker 2 is energized. Become.

  Further, even if the circuit breaker 2 is operated and interrupted, the load current d can be continuously supplied to the load 3, so that the load 3 connected to the circuit breaker 2 does not fail. . This eliminates the need for power failure countermeasures associated with the overcurrent interrupt function test of the circuit breaker 2 for wiring, and the circuit breaker 2 used for important circuits such as electrical circuits that are supplied to disaster prevention facilities is difficult. Also, the overcurrent interruption function test can be easily performed. As a result, the deterioration state of the circuit breaker 2 can be grasped, and the safety of the electrical equipment including the circuit breaker 2 can be further increased.

  Furthermore, since the test pole of the circuit breaker 3 for wiring can be switched only by the switch operation of the switching means 14, the operator switches the connection of the test line 4 with a live line such as the distribution line PL when switching the test pole. Is no longer necessary. For this reason, since work with danger can be reduced, the test can be performed regardless of the skill level of the operator, and the test time can be shortened.

  Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there is a design change or the like without departing from the spirit of the present invention, Included in the invention. For example, in Embodiment 1 described above, the Schottky barrier diode is described as the rectifying element of the bypass circuit 15, but an electronic element having a rectifying action such as a diode may be used.

DESCRIPTION OF SYMBOLS 1 Uninterruptible testing equipment 2 Circuit breaker for wiring 3 Load 4 Test line 11 Low voltage large current insulation type power supply (test power supply means)
12 Voltage detection means 13 Power supply cutoff means 14 Switching means 15 Bypass circuit (bypass means)
CB1 1st switch CB2 2nd switch CB3 3rd switch CB4 4th switch SW1 1st changeover switch SW2 2nd changeover switch T1 Test power supply side terminal T2 Test power supply side terminal P1 Electric wire side positive electrode Terminal N1 Electric wire side negative terminal P2 Load side positive terminal N2 Load side negative terminal PL Distribution line (electric wire)
LP Positive side wire LN Negative side wire

Claims (2)

An uninterruptible testing device that performs an overcurrent cutoff function test of a circuit breaker installed between an electric wire and a load,
Test power supply means for supplying a test current to the circuit breaker for wiring;
Voltage detection means for detecting a voltage by the test power supply means;
When the voltage detected by the voltage detection means is equal to or higher than a predetermined voltage, a power cutoff means that shuts off the test power supply means;
Switching means for switching the connection between the circuit breaker for wiring and the test power supply means;
Bypass means for supplying a load current from the electric wire to a load connected to the circuit breaker when the circuit breaker is interrupted by the test current, Uninterruptible testing equipment. An uninterruptible test method for conducting an overcurrent cutoff function test of a circuit breaker installed between an electric wire and a load,
Supplying a test current to the circuit breaker;
When the circuit breaker for wiring is interrupted by the test current, the load current connected to the circuit breaker for wiring is bypassed and supplied from the electric wire,
An uninterruptible testing method for a circuit breaker for wiring, characterized in that the supply of the test current is cut off when a voltage generated by the flow of the test current exceeds a predetermined value.

Images