JPH0440923B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a distribution board.

In a conventional distribution board that is equipped with a main breaker and a branch breaker and employs an earth leakage breaker as the main breaker, when the main breaker detects an earth leakage current and trips, which branch circuit has the earth leakage occurred? It is difficult to determine whether the current is present, and restoration is time-consuming, and during that time the power supply is stopped even to branch circuits that were not affected by the leakage accident, which can lead to secondary disasters.

Therefore, an object of the present invention is to provide a distribution board in which an earth leakage breaker is installed in the main trunk, and to easily and reliably identify a branch circuit in which an earth leakage is occurring even after the main earth leakage breaker is tripped. The aim is to provide a distribution board that can

An embodiment of the invention is shown in FIGS. 1 and 2. That is, this distribution board includes a master earth leakage breaker 1 installed at the main trunk, branch breakers 2 installed in each branch circuit, and each branch circuit breaker 2 on the front panel of the distribution board corresponding to the installation position of each branch breaker 2. The energization/current display means includes an energization display means disposed at a position to indicate energization of each branch circuit, and an earth leakage display means for indicating an earth leakage.
An earth leakage indicator lamp 3..., an energization detection circuit 4 that detects the energizing current of the branch circuit via a current transformer CT disposed in the primary side branch path of each of the branch breakers 2, and each of the branch breakers 2 an earth leakage detection circuit 5 which is arranged in the primary side branch path of the circuit and detects earth leakage current in the branch circuit via a zero-phase current transformer ZCT; and a corresponding energization detection circuit 4 which is provided correspondingly to each branch circuit.
An earth leakage display that receives a detection signal from the corresponding electricity/earth leakage indicator lamp 3 to display electricity, and receives a detection signal from the corresponding earth leakage detection circuit 5 and drives the corresponding electricity/earth leakage indicator lamp 3 to display electricity. Means: An indicator light driver circuit 6 including a driver circuit, an energization detection circuit 4, an earth leakage detection circuit 5, and an indicator light driver that are supplied with power from the primary main path of the main earth leakage breaker 1 and are arranged corresponding to each of the branch circuits. It is provided with a DC power supply circuit 8 that supplies DC current to each detection circuit section 7 consisting of a circuit 6. In FIG. 1, 2a is a tripping device for the branch breaker 2.

The main earth leakage breaker 1 includes a zero-phase current transformer ZCT ₁ that detects the earth leakage current flowing through the main, an earth leakage detection circuit 1a that determines the occurrence of an earth leakage accident from the detection signal of this zero-phase current transformer ZCT ₁ , and an earth leakage It includes a switching circuit 1b that performs a switching operation upon receiving an output signal from a detection circuit 1a, and a tripping device 1c that trips and drives a contact in response to the switching operation.

Each of the energization/leakage indicator lights 3 includes an LED 3a that emits red light to indicate energization, and an LED 3a that emits green light to indicate electricity leakage.
A pair of LEDs 3b are arranged in a display transparent body (not shown) disposed at a position corresponding to each branch breaker 2 on the front panel of the distribution board, and each of these LEDs 3a, 3b and the above-mentioned It is connected to the indicator light driver circuit 6 by the circuit configuration shown in FIG. That is, the indicator light driver circuit 6 includes a first switching circuit 6a including two transistors Q ₁ and Q ₂ connected in series to the positive side of the DC power supply circuit 8, and a second switching circuit 6b including a thyristor SCR. By turning on the transistors Q ₁ and Q ₂ of the first switching circuit 6a, the DC power supply voltage V _cc is applied to the energization display LED 3.
a, and the second switching circuit 6b
When the thyristor SCR is turned on, the DC power supply voltage _Vcc is applied to the earth leakage indicating LED 3b.

The transistor Q ₂ is turned on upon receiving a current conduction detection signal outputted from the current conduction detection circuit 4 via the resistor R ₃ at its base, and the thyristor SCR receives a leakage detection signal outputted from the leakage detection circuit 5 at its gate terminal. When no leakage detection is performed, the transistor _Q1 is turned on by the bias applied by the series circuit of resistors _R1 , _R2 , LED3b, and resistor _R6 , and the first switching circuit 6a is turned on (i.e., turned on). Transistors Q ₁ and Q ₂ are turned on), and LED 3a for electricity indication lights up (at this time, the electricity leakage indication
(Since the voltage applied to LED 3b is low, LED 3b does not light up), and when an earth leakage is detected, the thyristor SCR of the first switching circuit 6a turns on and the earth leakage display LED 3b lights up, while the resistance
As the voltage across R ₆ increases, transistor Q ₁
The bias of increases to turn off transistor _Q1 ,
The energization display LED 3a is turned off.

For earth leakage indication due to thyristor SCR ON operation
Since the lighting of the LED 3b is maintained by the self-holding function of the thyristor SCR, as shown in Fig. 1, the DC power supply circuit 8 and each display are used as an earth leakage display reset means to recover after the earth leakage accident has been restored. A return button 9 for resetting the earth leakage display with a normally closed contact is provided in the middle of the line connecting the lamp driver circuit 6, and the return button 9 for resetting the earth leakage display is momentarily turned off to achieve the return.

In addition, an earth leakage detection circuit 5 installed in each branch circuit
In other words, the time lag between detecting earth leakage and actually outputting a detection output (to prevent malfunction, the delay time is set so that it will not operate unless it continues for a specified period of time even if a leakage current of a specified level or higher flows) ) is set shorter than the operating time of main earth leakage breaker 1 (approximately 1/2 to 2/3 of the operating time of main earth leakage breaker 1), and the earth leakage detection sensitivity is also set higher than that of main earth leakage breaker 1 (main earth leakage breaker 1/2 to 2/3) of the detection level of 1) to avoid the inconvenience that would occur if the main power supply was cut off before the earth leakage display function was activated.

In this embodiment, the energization/leakage indicator lamp 3 is configured to have both the functions of energization display and earth leakage display, but the current leakage display may be performed separately from the energization display. It is not necessarily necessary to arrange it on the front panel of the electricity distribution board, but it may be installed inside the electricity distribution board.

Furthermore, the earth leakage display means is not limited to the above-mentioned configuration using an indicator light, but may also be a display means with a latch function that receives the output of the earth leakage detection circuit 5 and displays the display functionally, allowing the display to be reset manually. The DC power supply circuit 8 may also be provided with a separate battery.

With this configuration, the following effects can be obtained.

(1) Main earth leakage breaker 1 in the event of an earth leakage accident
Even after the circuit has tripped, it is possible to easily identify the branch circuit in which the current leakage has occurred, allowing for quick response to the current leakage accident, and by turning off only the branch breaker 2 of the branch circuit in question, By turning on the branch breaker, other branch circuits can be used in parallel with the repair of the branch circuit affected by the accident, minimizing the occurrence of secondary disasters and operational declines due to electrical leakage accidents. be able to.

(2) Since the operating time of the earth leakage detection circuit 5 installed in each expander circuit is set to be shorter than the operating time of the main earth leakage breaker 1, it is possible to reliably display the earth leakage before the main circuit is shut off. .

(3) In addition, since the earth leakage detection sensitivity of each earth leakage detection circuit 5 is set higher than the earth leakage detection sensitivity of the main earth leakage breaker 1, an earth leakage display is performed even when the main earth leakage breaker 1 does not trip, and the earth leakage can be easily detected. Accidents can be detected.

In addition to the earth leakage detection circuit 1a, the master earth leakage breaker 1 is equipped with another earth leakage detection circuit that senses a leakage current of about 1/2 of the breaking sensitivity current value and issues an earth leakage notice. An earth leakage accident in a branch circuit can be dealt with at a stage when the degree of earth leakage is relatively light before the earth leakage breaker 1 trips, and it is inconvenient that power supply to branch circuits that are not affected by the earth leakage accident is stopped. can be definitely avoided.

As described above, the distribution board of the present invention includes a main earth leakage breaker provided in the main, a branch breaker provided in each branch circuit, an earth leakage display means provided corresponding to each branch circuit, and each branch circuit. an earth leakage display means driver circuit provided corresponding to each branch circuit and configured to continuously drive the earth leakage display means in response to a detection signal of the corresponding earth leakage detection circuit; and the earth leakage display means. an earth leakage display reset means for resetting the earth leakage display state of the earth leakage display means, the DC power supply circuit of the earth leakage display means driver circuit receives power from the primary side main line of the main earth leakage breaker, and the earth leakage detection sensitivity of the earth leakage detection circuit. is set higher than the earth leakage detection sensitivity of the master earth leakage breaker, and the operation time of the earth leakage detection circuit is set shorter than the operation time of the master earth leakage breaker, so the following effects are obtained.

That is, even if a large leakage current flows for a short period of time, the leakage is always detected by the leakage detection circuit and the leakage is displayed by the leakage display means before the main leakage breaker trips. Furthermore, even if the master earth leakage breaker does not trip, an earth leakage display is displayed, making it easy to discover an earth leakage accident. Furthermore, since the DC power supply circuit of the earth leakage indicator driver circuit receives power from the primary main path of the main earth leakage breaker, the earth leakage indicator driver circuit continues to display the earth leakage without stopping even after the main earth leakage breaker trips. This makes it possible to easily and reliably identify the branch circuit in which a current leak has occurred, allowing prompt response to the current leakage accident, and turning off only the branch breaker of the branch circuit in question By turning on the branch breaker, other branch circuits can be used in parallel with the repair of the branch circuit affected by the accident, minimizing the occurrence of secondary disasters and operational declines due to electrical leakage accidents. It has the effect of being able to.

[Brief explanation of the drawing]

FIG. 1 is a schematic circuit diagram showing an embodiment of the present invention, and FIG. 2 is a detailed circuit diagram of the main part thereof. DESCRIPTION OF SYMBOLS 1... Main earth leakage breaker, 2... Branch breaker, 3... Energization/earth leakage indicator light including an earth leakage indicator, 5... Earth leakage detection circuit, 6... Indicator light driver circuit including an earth leakage indicator driver circuit, 8 . . . DC power supply circuit, 9 . . . A return button for resetting the earth leakage display, which is a means for resetting the earth leakage display.

Claims (1)

[Claims] 1 A master earth leakage breaker installed in the main trunk, a branch breaker installed in each branch circuit, an earth leakage display means provided corresponding to each branch circuit, an earth leakage detection circuit installed in each branch circuit, and each branch an earth leakage display means driver circuit provided corresponding to the circuit and configured to continuously drive the earth leakage display means in response to a detection signal of the corresponding earth leakage detection circuit; and an earth leakage display reset means for resetting the earth leakage display state of the earth leakage display means. The DC power supply circuit of the earth leakage display means driver circuit receives power from the primary main path of the main earth leakage breaker, and the earth leakage detection sensitivity of the earth leakage detection circuit is higher than the earth leakage detection sensitivity of the main earth leakage breaker. and further set the operation time of the earth leakage detection circuit to be shorter than the operation time of the master earth leakage breaker.