JPH01231619A - Alarm device for electronic circuit breaker - Google Patents

Abstract

PURPOSE:To prevent the distribution system against dysfunction, by detecting the abnormality before a circuit breaker is actuated in the wide range in case the load condition of the breaker is abnormal. CONSTITUTION:Load current is detected by a current transformer 1 and inputted to an electronic circuit 4, through which the inputted secondary voltage Vg of the maximum phase in load with a rectification maximum phase detection circuit 5. Signals are sent to an instantaneity circuit 6 different in operation time limit according to the size of the secondary voltage Vg, a short time limit circuit 7, a long time limit circuit 8, actuating a magnetism tripping device 3 to open a breaker mechanism section 2 and to perform the circuit breaker operation. On the other hand, a signal 11a generated by inputting the secondary voltage Vg to a secondary voltage comparison and time extension circuit 11 and a signal 8b generated in the limit time earlier than the time limit of the signal 8a sent out from a counting circuit 9 in the long time limit circuit 8 to a trigger circuit 10 are ANDed with a diode 12 of an AND circuit. With this logic signal an alarm output of an alarm circuit 13 is issued and it turns ON an alarm lamp of an external location alarm device 14.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an electronic circuit breaker using an electronic circuit in the detection section, and is particularly suitable for use as a main circuit breaker in a complex system with many loads in a power distribution system. The present invention relates to an alarm device for an electronic circuit breaker suitable for early detection of system abnormalities such as overload conditions.

[Conventional technology]

Conventional electronic circuit breaker alarm devices detect overload conditions that exceed the rated current and flash a light emitting element on the surface of the circuit breaker to indicate the overload, or provide an overload alarm contact to issue an external alarm. I'm trying to make it possible. Additionally, some circuit breakers are used in air circuit breakers, etc., and are designed to operate for a fixed time delay in a fixed current range from a current below the rated current to a limited overload current.

[Problem to be solved by the invention]

In the above conventional technology, one is that the alarm device does not work unless there is an overload condition, and the other is that the operating value can be lowered to the rated current or less, but if the load current is, for example, 200% of the rated current. In the above case, the tripping operation occurs before the alarm is issued, so
It operates and issues an alarm within a limited range of overload conditions and after a certain delay time regardless of the current value, so it is not effective for early detection of system abnormalities such as overload conditions. There was a problem.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an alarm device for an electronic circuit breaker that operates below the rated current and has a wide operating range that can operate before tripping in an overload condition. be.

[Means to solve the problem]

The above purpose is to install a comparison/time delay circuit with an independent operating value and operating time in parallel with a tripping circuit in a circuit that generates a signal proportional to the load current in an electronic circuit breaker that uses an electronic circuit in the detection section. An electronic element contact of the alarm circuit that operates by ORing the signal generated at a specified time during the tripping circuit's time delay operation and the signal generated by the independent comparison/time delay circuit to output an alarm. When the load current exceeds the first reference value which is less than the rated current, it will operate after a certain delay time and issue an alarm, and when the load current exceeds the operating value of the tripping circuit and exceeds the second reference value, it will operate and issue an alarm. This is achieved by an alarm device for an electronic circuit breaker configured to operate and issue an alarm after a delay time of, for example, half of the operating time of the circuit breaker depending on the magnitude of the load current when the circuit breaker is in a loaded state.

[Effect]

In the above-mentioned electronic circuit breaker alarm device, the load current is converted to a secondary current by an amperage meter in the detection section of the circuit breaker and inputted to the electronic circuit, and the secondary current is converted to voltage within the electronic circuit. The time delay circuit of the tripping circuit is activated by the signal of the secondary voltage, but the signal of this secondary voltage is compared with the comparison/time delay circuit and a signal with a certain time delay taken by the CR time constant etc. is generated. At the same time, the signal generated at a specified time during the operation to delay the trip circuit is extracted, and the OR signal of both signals is used to switch the electronic element contact of the alarm circuit, and the first criterion is that the current is below the rated current. When the value is exceeded, a signal from the comparison/time delay circuit issues an alarm after a certain delay time, and
When the overload condition exceeds the second reference value that exceeds the operating value of the tripping circuit, the circuit breaker operates according to the magnitude of the load current by a signal generated at a specified time during the operation to delay the tripping circuit. By issuing the alarm after a delay of, for example, half of the time, it is possible to operate the externally mounted alarm device over a wide operating range.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a block diagram of an electronic circuit section of an electronic circuit breaker showing an embodiment of an alarm device for an electronic circuit breaker according to the present invention. In FIG. 1, 1 is a current transformer, 2 is a circuit breaker mechanism, 3 is a magnetic trip device, and 4 is an electronic circuit of a detection section. 5 is a rectifier/maximum sum detection circuit of the load detection circuit section, 6 is an instantaneous circuit of the tripping circuit section, 7 is a short time limit circuit, 8 is a long time limit circuit, 9 is a counting circuit, 10 is a trigger circuit, and 11 is an alarm circuit. 12 is a diode of an OR circuit, and 13 is an alarm circuit. 14 is an externally installed alarm device, 15 is an alarm display lamp, and 16 is a power source.

With the above configuration, the load current of the circuit is detected by the current transformer 1 of the detection section, converted to a secondary current, and then inputted to the electronic circuit 4, and the electronic circuit 4 of the detection section converts the input secondary current to the load detection circuit. The rectifier/maximum sum detection circuit 5 converts it into the secondary voltage Vg of the maximum load phase, and the instantaneous circuit 6, short time limit circuit 7, and long The trigger circuit 10 is activated by combining the time delay circuits of the time limit circuit 8.
The output of the trigger circuit 10 operates the magnetic tripping device 3 to open the circuit breaker mechanism 2, thereby performing a circuit breaking operation. On the other hand, the secondary voltage Vg of the rectifier/maximum phase detection circuit 5 is connected to the output of the alarm circuit section, which has an independent operating value and operating time limit, and a tripping circuit is provided in parallel.
input to the time delay circuit 11, and this secondary voltage comparison/time delay circuit 1
1 generated signal 11a and a signal 8a sent from the counting circuit 9 in the long time limit circuit 8 of the tripping circuit to the trigger circuit 10.
The diode 12 of the OR circuit performs a logical sum with the signal 8b generated at a specified time earlier than the time limit of , and this logical sum signal operates the electronic element contact of the alarm circuit 13 to issue an alarm output. The alarm display lamp 15 of the externally installed alarm device 14 is turned on from I and T 2.

FIG. 2 is a detailed circuit diagram of the alarm circuit section of FIG. 1. Second
In the figure, u1 to u7 are comparators, u8. u9 is the counter IC, DI, D2 is the diode 12, D3 is the rectifier stack, Tr is the electronic element contact transistor, FE
T is a field effect transistor, C1 to C4 are capacitors,
R1-R24 are resistors.

In the above configuration, the secondary voltage Vg of the rectification/maximum phase detection circuit 5, which changes depending on the load current, is determined by the secondary voltage comparison of the alarm circuit section.
It is input to the time delay circuit 11 and the long time delay circuit 8 of the tripping circuit section. In the secondary voltage comparison/time delay circuit 11, comparator u1
Compare the secondary voltage Vg and the threshold value Vthl and get the value Vg)
When the voltage is Vthl, a time delay is provided by the resistor R3 and the capacitor C1, the comparator u2 is turned off after a certain delay time T1, and the signal 11a is input to the alarm circuit 13 through the diode Di (12). In one long time limit circuit 8, comparator u3. The long time pickup value is detected by u4, and the comparator u5. u6. u7, capacitor C4, resistor R
18 generates a pulse, and the pulse is sent to the counting circuit 9.
Counter lCu8. Input it to u9 and let it count. The output Q1 of the counter I Cu9 of the counting circuit 9 is the counter IC
For example, the pulse input to clock pulse input C of u8 is 64
The output Q2 changes from a low level to a high level at the 12828th time, for example, when the same pulse is applied for the 12828th time. The signal 8b of the output Q1 is inputted to the alarm circuit 13 through the diode D2, and the signal 8a of the output Q2 is inputted to the trigger circuit 10, so that the magnetic exception device 3 causes the circuit breaker mechanism 2 to perform a breaking operation. In this way, the signal 8b at the output Q1 rises at a delay time that is, for example, half the time at which the signal 8a at the output Q2 appears. When the transistor Tr of the alarm circuit 13 is turned ON by this signal 8b, the field effect transistor FET is turned ONL and the terminal T1. , the alarm indicator lamp 15 of the externally installed alarm device 14 connected to T2, or a buzzer (not shown), etc., operates. The use of rectifier stack D3 allows the use of both traffic sources for the power source 16 of the externally mounted alarm device 14.

FIGS. 3(a), (b), and (c) are operational characteristic diagrams of the alarm circuit section in FIG. 1 (FIG. 2), and FIG. Characteristics due to signal 11a, Fig. 3(b)
is the characteristic due to the signal 8b of the counting circuit 9 in the long time limit circuit 8,
FIG. 3(c) shows the characteristics of the logical sum signal of both signals.

Figure 3(a).

In (b) and (C), the horizontal axis shows the load current ■, the vertical axis shows the operating time T, A is the operating characteristic curve of the circuit breaker, Bl
, B2. B is the operating area (shaded area) of the alarm circuit, and Ir is the rated current. The alarm circuit 13 is operated in the shaded area B.
l, B2. At B, the circuit breaker continues to operate until the operating time limit according to the operating characteristic curve A of the circuit breaker according to the signal from the trigger circuit 10. The operating characteristic of FIG. 3(a) is that the diode 12 is
(Dl) from the alarm circuit 13, for example, when the load current exceeds 80% of the rated current Ir, the constant time - extended time T1
The circuit breaker operates after the fixed time delay time T1 is a constant value even if the current value becomes large, and the circuit breaker operates at constant time = 8 - delay time T1.For example, the circuit breaker operates after the rated current Ir.
It operates in the operating region B1 up to the load power level 1, which is close to 200%. Due to the operating region B1 of this characteristic, the alarm circuit 13 operates even with a load current below the rated current Ir, so when the circuit breaker is used as a main breaker, there are many energized states where the rated current is below Ir, and when the rated current Ir This is effective because there are many cases where an abnormality occurs even when the load current is about 80%.

The operating characteristic of FIG. 3(b) is that of the counting circuit 9 in the long time limit circuit 8.
The diode 12 (
D2) from the alarm circuit 13, and the rated current Ir
With the above load current, the circuit breaker starts operating in a delay time that is half of the operating time when the circuit breaker is operated by the signal 8a of the long time limit circuit 8 (signal of the output Q2), and the circuit breaker opens in the operating region B2. Operate. Due to the operating region B2 of this characteristic, in the long time region of the operating characteristic curve A of a circuit breaker with a rated current Ir or more, the alarm circuit 13 is always activated in the operating time of the inverse time characteristic that changes depending on the magnitude of the load current peak. can work. Furthermore, even if the circuit breaker operates, if the alarm time is memorized, the magnitude of the load current can be determined. Third
The operating characteristics shown in Figure (c) are a combination of the two characteristics shown in Figures 3 (a) and (b), and are the characteristics of the secondary voltage comparison/time delay circuit 1.
1 signal 11a and the signal of the counting circuit 9 in the long time limit circuit 8 (
output Q1 signal) respectively through diodes 12 (Di, D
2) is obtained from the alarm device 13 by the logical sum signal obtained by performing the logical sum. Due to the operating region B of this characteristic, when the load current is below the rated current Ir, for example above the first reference value of 80%, the alarm circuit 13 operates after a certain delay time T1, and the operating value of the tripping circuit is Load current exceeding ■
In a long time delay region equal to or greater than the second reference value, the alarm circuit 13 operates with a delay time of inverse time delay characteristics according to the load current, and exhibits characteristics with a wide operating range. Note that if the value of the resistor R2 of the secondary voltage comparison/time delay circuit 11 in FIG. 2 is made variable, the alarm circuit 13
The operation starting current value can be easily changed.

〔Effect of the invention〕

According to the present invention, when the load condition of a circuit breaker is abnormal, the abnormality can be detected before the circuit breaker operates in a wide range, so there is an effect that system failure of the power distribution system can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an electronic circuit showing an embodiment of the alarm device for an electronic circuit breaker according to the present invention, Fig. 2 is a detailed circuit diagram of the alarm circuit section of Fig. 1, Fig. 3(a), (b), (C
) is an operational characteristic diagram of the alarm circuit section of FIG. 1 (FIG. 2). DESCRIPTION OF SYMBOLS 1... Current transformer, 2... Breaker mechanism part, 3... Magnetic removal device, 4... Electronic circuit, 5... Rectification/maximum phase detection circuit, 6... Instantaneous circuit , 7... short time circuit, 8
... Long time limit circuit, 9... Counting circuit, 10... Trigger circuit, 11... Secondary voltage comparison/time delay circuit, 12.
...Diode, 13...Alarm circuit, 14...Externally installed alarm device.

Claims (1)

[Claims] 1. In an electronic circuit breaker that uses an electronic circuit in the detection part, the output of the circuit that obtains the signal according to the load current has an independent operating value and operating time in parallel with the tripping circuit.
A time delay circuit is provided, and a signal generated at a specified time during the operation to delay the trip circuit is compared with a signal generated by the time delay circuit to issue an alarm output. When the current exceeds a first reference value that is below the rated current, an alarm is issued after a certain delay time, and when the current exceeds a second reference value that exceeds the operating value of the tripping circuit, an alarm is issued depending on the magnitude of the load current. What is claimed is: 1. An alarm device for an electronic circuit breaker, characterized in that the alarm device is configured to issue an alarm after a delay time having an inverse time limit characteristic.