JP2020137241A - Power supply line abnormality detection method for electric load system - Google Patents

Abstract

To provide a power supply line abnormality detection method for electric load apparatuses for enabling an electric load system that has a plurality of electric load apparatuses connected in parallel to a power supply and synchronously supplies power to perform parallel operation, to simply and inexpensively detect power supply line abnormality such as disconnection and poor connection of respective power supply lines connected to the electric load apparatuses.SOLUTION: A power supply line abnormality detection method for an electric load system includes: detecting, by power supply line abnormality detection means (13) on the basis of a magnetic field caused by current of power supply lines (15a-15c, 17a-17c) connected in parallel to respective electric load apparatuses (5, 7), the whole current of the power supply lines; when a detected current value is equal to or lower than a reference current value (Iref.), determines that normal conduction is performed in the respective power supply lines (15a-15c, 17a-17c) and continues synchronous supply of power to the respective electric load apparatuses (5, 7) to make the apparatuses perform parallel operation; and, when the detected current value is equal to or higher than the reference current value (Iref.), determines that abnormal conduction occurs in any of the respective power supply lines (15a-15c, 17a-17c) and intercepts synchronous supply of power to the respective electric load apparatuses (5, 7) to make the apparatuses stop parallel operation.SELECTED DRAWING: Figure 1

Description

The present invention includes a power source (including a DC power source, a single-phase AC power source, and a three-phase AC power source. When the electric load device is a servomotor, the power source is a DC component composed of a main circuit unit and a control circuit unit. Or, it includes a type in which power is supplied from the main circuit of an AC servo amplifier.) A power line abnormality that detects a power line abnormality such as a disconnection or poor connection in an electric load system in which multiple electric load devices are connected in parallel. Regarding the detection method.

For example, in an AC electric device as various electric load devices connected to a three-phase AC power source as a power source, three phases (R phase, S phase, and T phase) having different phases are used as shown in Patent Document 1. A current detector and each current detector that detect the current flowing through the disabled power generator that is connected to the ends of the three power supply lines (distribution lines) that supply the three-phase AC power that are configured to generate the disabled power. Each is provided with a disconnection detection device equipped with a disconnection determination unit that determines whether or not the distribution wire is disconnected based on the detected current value, and the current value detected by each current detection unit is less than a predetermined reference current value. In this case, it is determined that the corresponding distribution wire is broken, and it is prevented that the AC electric power equipment is burnt out due to overheating due to an abnormal current, or malfunctions due to a torque abnormality.

Then, when driving a high-load device (equipment), for example, instead of a high-output three-phase AC electric device, a plurality of three-phase AC electric devices having the same rating are connected in parallel to a three-phase AC power supply. In some cases, a three-phase AC power is supplied synchronously to form an electric load system that operates in parallel. In such an electric load system, in order to detect disconnection or poor connection of the power line of each phase connected to each three-phase AC electric device, each three-phase AC electric device has its own power line for each phase. The disconnection detection device of Patent Document 1 is attached to enable detection of power line abnormalities such as disconnection of the power line of each phase and poor connection in each three-phase AC electric device.

However, in order to detect an abnormality in the power supply line in the above-mentioned three-phase AC electric load system, a disconnection detection device for each phase must be provided for each three-phase AC electric device, and the entire electric load system (three) Since the number of installed phase-AC electric devices x 3) requires a disconnection detection device, there is a problem that the configuration of the electric load system becomes complicated and the cost of the system itself increases.

The same problem as described above occurs when the power source of the electric load system is a DC power source or a single-phase AC power source, and the electric load device is a DC electric load device or a single-phase AC electric load device.

Japanese Unexamined Patent Publication No. 2016-27306

The problem to be solved is to detect power line abnormalities such as power line disconnection and poor connection in an electric load system that connects multiple electric load devices in parallel to the power supply and supplies power synchronously to operate in parallel. In order to do so, it is necessary to install a disconnection detection device on each electric wire for each electric load device, and the number of disconnection detection devices installed increases, which complicates the electrical load system and increases the cost.

The first aspect of the present invention is an electric load system in which a plurality of electric load devices are connected in parallel to a power source, and electric current is synchronously supplied to each electric load device for parallel operation, and the electric load devices are connected in parallel to each electric load device. The current of the entire power supply line is detected by the power supply line abnormality detecting means based on the magnetic field generated by the current of the power supply line, and if the detected current value is less than or equal to the reference current value, it is judged that each power supply line is normally conducted. While the synchronous power supply to the electric load equipment is continuously operated in parallel, if the above-mentioned detected current value is equal to or higher than the reference current value, it is judged that one of the power supply lines has a continuity abnormality and the AC to each electric load equipment. The most important feature is to cut off the synchronous power supply and stop the parallel operation.

In the second aspect of the present invention, in the first aspect, the power line abnormality detecting means is an electromagnetic detection type that detects the magnetism generated by the current flowing through each power line inserted in the hollow portion of the core and outputs the detection current. The most important feature is what you have done.

In the third aspect of the present invention, in the second aspect, the power supply lines of each electric load device are inserted into the hollow portion of the core so as to have alternating current directions, and the current of the entire power supply line is detected by the power supply line abnormality detecting means. The most important feature is the electromagnetic detection of.

In the fourth aspect of the present invention, in any one of the first to third aspects, the power source is a three-phase AC power source whose phases are shifted by 120 degrees, and the electric load device is a three-phase AC power driven by the three-phase AC power. The most important feature is that it is an AC electric load device.

In the fifth aspect of the present invention, in the fourth aspect, the power lines of the three-phase AC electric load devices are in alternating current directions with respect to the hollow portion of the core, and the one-phase power lines of the three-phase AC electric load devices. The most important feature is that the current of the entire power line is electromagnetically detected by the power line abnormality detecting means by inserting the current so that the current direction is opposite to that of the other two-phase power lines.

In the sixth aspect of the present invention, the power source is a two-wire single-phase AC power source in any one of the first to third aspects, and the electric load device is a two-wire single-phase AC electric load driven by the single-phase AC power. The most important feature is that it is a device.

In the seventh aspect of the present invention, in the sixth aspect, the power supply lines of the two-wire single-phase AC electric load devices are inserted into the hollow portion of the core so as to have alternating current directions, and the power supply line abnormality detecting means is used. The most important feature is electromagnetic detection of the current of the entire power line.

The most main feature of the eighth aspect of the present invention is that the power source is a DC power source and the electric load device is a DC electric load device driven by DC power in any of the first to third aspects. To do.

In the ninth aspect of the present invention, in the eighth aspect, the power lines of each DC electric load device are inserted so as to be in alternating current directions in the hollow portion of the core, and the entire power line is detected by the power line abnormality detecting means. The most important feature is the electromagnetic detection of electric current.

In the tenth aspect of the present invention, the power supply line of the power supply and the power supply line of the electric load device conduct the detection current value detected by the power supply line abnormality detecting means in any of the fourth to ninth aspects in a normal state. If there is, the most important feature is that it is below the reference current value, and if the power supply line of the power supply and the power supply line of the electric load equipment are poorly connected, it is above the reference current value.

In the eleventh aspect of the present invention, when the detected current value is equal to or higher than the reference current value in any one of the first to tenth aspects and the synchronous power supply to each electric load device is cut off, the notification means is activated. The most important feature is that it is possible to notify the power line abnormality.

According to the present invention, in an electric load system in which a plurality of electric load devices are connected in parallel to a power source and power is supplied synchronously to operate in parallel, each power line connected to each electric load device is disconnected or poorly connected. Power line abnormality can be detected easily and at low cost.

It is explanatory drawing which shows the outline of the power line abnormality detection method when the electric load system is a three-phase AC electric load system. It is explanatory drawing which shows the power line abnormality detecting means. (A) is an explanatory diagram which shows the detected current value when the power line is a normal state. (B) is an explanatory diagram showing an output state of a disconnection signal. (A) is an explanatory diagram which shows the detected current value when the power line is in an abnormal state. (B) is an explanatory diagram showing an output state of a disconnection signal. It is explanatory drawing which shows the outline of the power line abnormality detection method of the 2-wire single-phase AC electric load system which concerns on Example 2. FIG. It is explanatory drawing which shows the outline of the power line abnormality detection method of the DC electric load system which concerns on Example 3. FIG.

The current of the entire power supply line is detected by the power supply line abnormality detecting means based on the magnetic field generated by the current of the power supply line connected in parallel to each electric load device, and if the detected current value is less than or equal to the reference current value, each power supply line is detected. Is judged to be normal continuity and the synchronous power supply to each electric load device is continuously operated in parallel. On the other hand, if the detected current value is equal to or higher than the reference current value, one of the power supply lines is judged to be abnormal continuity. The best embodiment is to cut off the synchronous power supply of AC power to each electric load device to stop the parallel operation.

Hereinafter, the present invention will be described with reference to the figure showing Example 1 in which the present invention is carried out in a three-phase AC electric load system.
As shown in FIG. 1, the three-phase AC electric load system 1 as an electric load system is a three-phase AC power supply 3 as a power source (when the electric load device is a three-phase AC servomotor, the main circuit section and the control circuit). The first and second three-phase electric motors 5 and 7 (in this example, two units) constitute AC electric load equipment with low output and the same rating, as opposed to the servo amplifier composed of parts as a three-phase AC power supply. However, the present invention is not limited to this, and it can be carried out even if there are three or more of them.) These first and second three-phase electric motors 5 and 5 are connected in parallel. It is configured to obtain high output as a whole system by synchronously supplying three-phase AC power to 7 and operating in parallel.

In the three-phase AC electric load system 1, the phase is shifted by 120 degrees as described above, and the voltage vectors are adjusted for the R-phase, S-phase, and T-phase three-phase AC power supplies 3 and the three-phase AC power supply 3. It is composed of two three-phase electric motors 5 and 7 which are connected in parallel via a switching means 11 and operated in parallel, and a power supply line abnormality detecting means 13. When the three-phase AC power supply 3 is used as a servo amplifier, the ON-OFF control by the switching means 11 is executed by the main circuit unit of the servo amplifier.

The power supply units (U, V, W) of the first and second three-phase electric motors 5 and 7 are connected to power lines 15a-15c, 17a- from the R phase, S phase, and T phase of the three-phase AC power supply 3. 17c are connected in parallel, and three-phase AC power is synchronously supplied to the first and second three-phase electric motors 5 and 7 by ON-OFF control of the switching means 11.

As shown in FIG. 2, the power line abnormality detecting means 13 has a ring shape or a horseshoe shape as a current transformer, and is driven by a current flowing through the power lines 15a-15c and 17a-17c inserted into the hollow portion of the penetrating core 13a. It is configured as a magnetic detector that detects the generated magnetic field by the detection coil 13b that is circulated around the core 13a and converts it into a detection current.

The detection coil 13b is connected to the comparison circuit 13d via an amplifier 13c connected as needed, and the comparison circuit 13d has a reference current value Iref. When the above occurs, a disconnection signal is output to the switching means 11 to cut off the power supply of the three-phase AC power to the first and second three-phase electric motors 5 and 7, and the alarm means and warning are given based on the disconnection signal. The notification means 13e such as the display means is operated to notify the operator of the power line abnormality.

In addition to the above, the power line abnormality detecting means 13 includes a conventionally known current such as a Hall element current detecting means in which a Hall element is provided in a through-type core and a current is detected by a magnetic field generated around an electric wire inserted in the hollow portion. It may be a detection means.

The reference current value Iref. Is actually minute in the inductance and resistance value (reactance) of the first and second three-phase electric motors 5 and 7, even when the ratings of the first and second three-phase electric motors 5 and 7 are the same. Since there are variations, the current value is set to an arbitrary value in consideration of these variations.

The power supply lines 15a-15c and 17a-17c are inserted into the hollow portion of the core 13a as follows, and the power line abnormality detecting means 13 detects a current conducting the power supply lines 15a-15c and 17a-17c. Will be done.

That is, it is connected to the power supply lines 15a-15c connected to the power feeding unit (U, V, W) of the first three-phase electric motor 5 and the power supply unit (U, V, W) of the second three-phase electric motor 7. The power lines 17a-17c have alternating current directions with respect to the hollow portion of the core 13a, and the power lines 15b and 17b thereof have current directions opposite to those of the other power lines 15a and 15c and 17a and 17c. It is inserted like this.

In the case where the AC electric device is composed of three three-phase electric motors, the three power lines connected to the third three-phase electric motor power supply unit are connected to the hollow portion of the core 13a. The power lines 15a-15c of the first three-phase electric motor 5 are inserted in the same manner. Further, in the case where the AC electric device is composed of four three-phase electric motors, the three power lines connected to the fourth three-phase electric motor power feeding unit are connected to the hollow portion of the core 13a. The second three-phase electric motor 7 is inserted in the same manner as the power supply lines 17a-17c.

The power lines 15a-15c and 17a-17c shown by the broken lines with respect to the core 13a in FIGS. 1 and 2 indicate the state of passing through the hollow portion of the core 13a and the power supply shown with a solid line with respect to the core 13a. Lines 15a-15c and 17a-17c indicate a state in which the core 13a is located outside the hollow portion (outer peripheral side), respectively.

Next, a power line abnormality detection method in the three-phase AC electric load system 1 will be described.
First, when all of the power lines 15a-15c and 17a-17c are non-disconnected and are conducting normally, or when the power supply units (U, V, W) of the three-phase electric motors 5, 7 and 9 are connected. On the other hand, when the corresponding power lines 15a-15c, 17a-17c, 19a-19c are normally electrically connected, the power lines 15a-15c, 17a- of each phase inserted into the hollow portion of the core 13a. Since the phases of the currents flowing through the 17c are shifted by 120 degrees, the detection current value from the detection coil 13b excited by the magnetic field generated around the power lines 15a-15c and 17a-17c is "0" in principle. "become.

However, even when the ratings of the first and second three-phase electric motors 5.7 are the same, there are slight variations in the inductance and resistance value (reactance), and the detected current value is not necessarily "0". Reference current value Iref. Since the following weak current values may occur, in the present invention, the detection current value when the power supply lines 15a-15c and 17a-17c are normally connected is used as the reference current value Iref. It is expressed as the approximate "0" below.

In this case, the detection current value detected by the power line abnormality detecting means 13 is the reference current value Iref. Since it is approximately "0" below, the comparison circuit 13d has three with respect to the first and second three-phase electric motors 5 and 7 by keeping the disconnection signal for the switching means 11 in the OFF (LOW) state. Synchronous power supply of phase AC power is continuously operated in parallel. (See FIGS. 3 (A) and 3 (B))

On the other hand, when any of the power supply lines 15a-15c and 17a-17c is disconnected and non-conducting, or when the power supply lines (U, V, W) for the first and second three-phase electric motors 5 and 7 are supplied. When the electrical connection of 15a-15c and 17a-17c is defective, one of the power supply lines 15a-15c and 17a-17c is out of phase and becomes unbalanced, which is detected by the power supply line abnormality detecting means 13. The detected current value to be detected is the reference current value Iref. Transition to the above.

In this case, the detection current value detected by the power line abnormality detecting means 13 is the reference current value Iref. Therefore, when the disconnection signal from the comparison circuit 13d is changed to ON (HIGH), the synchronous power supply of the three-phase AC power to the first and second three-phase electric motors 5 and 7 is cut off and the parallel operation is performed. At the same time as stopping, the notification means 13e is operated based on the disconnection signal to notify the operator of the power line abnormality. (See FIGS. 4 (A) and 4 (B))

The quasi-current value Iref. When the above detection current is detected, whether any of the power supply lines 15a-15c and 17a-17c is broken, and the power feeding units (U, U, 2) of the first and second three-phase electric motors 5 and 7. It is not possible to specify which of the power lines 15a-15c and 17a-17c is poorly connected to V, W), but the synchronous power supply of the three-phase AC power to the first and second three-phase electric motors 5 and 7 is cut off. By doing so, it is possible to prevent the excitation coils in the first and second three-phase electric motors 5 and 7 from being burnt out or abnormal output.

In this embodiment, the magnetic field due to the current flowing through the power lines 15a-15c and 17a-17c is magnetically detected by one power line abnormality detecting means 13, and the power lines 15a-15c and 17a- based on the detected current values. It is possible to detect power line abnormalities such as disconnection and poor connection of 17c, and it is simpler and lower than the conventional power line abnormality detection method that detects power line abnormality by providing a disconnection detection device in the power line of each phase. Power line abnormalities can be detected at a cost.

Example 1 has been described by using a three-phase AC power supply as an AC power source and a three-phase AC electric load system using an AC electric device as a three-phase electric motor, but in Example 2, the power source is a single-phase AC power source and an electric load device. This will be described as a single-phase AC electric load system composed of a single-phase AC electric motor. The same members as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 5, the single-phase AC electric load system 21 is composed of a single-phase AC power supply 23 as a power source (when the AC electric load device is a single-phase AC servomotor, it is composed of a main circuit unit and a control circuit unit. The first and second single-phase AC electric motors 25 and 27 (in this example, two single-phase AC electric motors) as electric load devices with low output and the same rating, as opposed to the servo amplifier to be used as an AC power supply. However, the present invention is not limited to this, and can be carried out even if there are three or more units) connected in parallel to these first and second single-phase AC electric motors 25 and 27. It is configured to obtain high output as a whole system by synchronously feeding single-phase AC power and operating in parallel.

Even in this case, the power lines 29a / 29b and 31a / 31b for connecting the single-phase AC power supply 21 and the first and second single-phase AC electric motors 25 and 27 in parallel are as follows with respect to the hollow portion of the core 13a. The currents of the power supply lines 29a / 29b and 31a / 31b are detected by the power supply line abnormality detecting means 13.

That is, the power supply lines 29a and 29b connected to the power feeding portions (A and B) of the first single-phase AC electric motor 25 are inserted through the hollow portions of the core 13a so that the current directions are staggered. Further, in the power supply lines 31a and 31b connected to the power supply portions (A and B) of the second single-phase AC electric motor 27, the power supply line 31a is opposite to the current direction of the power supply line 29a with respect to the hollow portion of the core 13a. The power line 31b is inserted in the direction and in the direction opposite to the current direction of the power line 29b.

When the AC electric load device is composed of three single-phase AC electric motors, the two power supply lines connected to the power supply section of the third single-phase AC electric motor are connected to the core 13a. It is inserted into the hollow portion in the same manner as the power supply lines 29a and 29b of the first single-phase AC electric motor 25. Further, in the case where the AC electric device is composed of four single-phase AC electric motors, the two power supply lines connected to the power feeding unit of the fourth single-phase AC electric motor are hollow of the core 13a. It is inserted into the unit in the same manner as the power supply lines 31a and 31b of the second second single-phase AC electric motor 27.

Even when the AC electric devices are the first and second single-phase AC electric motors 25 and 27, each phase when the current flowing through the power lines 29a / 29b and 31a / 31b passes through the hollow portion of the core 13a. If the power lines 29a / 29b and 31a / 31b are not disconnected or the connection is normal, the magnetic field generated by the currents of the wires 29a / 29b and 31a / 31b will be generated. In the balanced state, the detection current value detected by being excited by the detection coil 13b is the reference current value Iref. It becomes the following approximate “0”, and the power supply of AC power to the first and second single-phase AC electric motors 25 and 27 is continuously operated in parallel.

On the contrary, when the power supply lines 29a / 29b, 31a / 31b are disconnected or poorly connected, the magnetic field generated by the currents of the electric wires 29a / 29b, 31a / 31b transitions to the non-equilibrium state and is excited by the detection coil 13b. The detected current value detected is the reference current value Iref. As described above, when the disconnection signal from the comparison circuit 13d transitions to ON (HIGH), the synchronous power supply of the single-phase AC power to the first and second single-phase AC electric motors 25 and 27 is cut off, and the disconnection signal is generated. Based on this, the notification means 13e is operated to notify the operator of the power line abnormality.

Examples 1 and 2 have been described based on an electric load system composed of an AC power supply (three-phase AC power supply and a single-phase AC power supply) and an AC electric load device (three-phase AC electric motor and a single-phase AC electric motor). However, the third embodiment will be described based on a DC electric load system in which the power supply is a DC power supply and the electric load device is a DC electric motor. The same members as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 6, the DC electric load system 41 uses a DC power supply 43 as a power source (when a DC electric load device is a DC servomotor, a servo amplifier composed of a main circuit unit and a control circuit unit is DC. The first and second DC electric motors 45 and 47 (in this example, two DC electric motors are used as DC electric load devices having low output and the same rating as the power source), but the present invention is based on this. It is possible to carry out even if there are three or more units without limitation.) Connect them in parallel, and supply DC power to these first and second DC electric motors 45 and 47 in parallel to operate them in parallel. Is configured to obtain high output as a whole system.

Even in this case, the power supply lines 49a / 49b and 51a / 51b for connecting the DC power supply 43 and the first and second DC electric motors 45/47 in parallel are inserted into the hollow portion of the core 13a as follows. Then, the power line abnormality detecting means 13 detects the currents flowing through the power lines 49a / 49b and 51a / 51b.

That is, the power supply lines 49a and 49b connected to the power feeding portions (A and B) of the first DC electric motor 45 are inserted through the hollow portions of the core 13a so that the current directions are staggered. Further, in the power supply lines 51a and 51b connected to the power supply portions (A and B) of the second DC electric motor 47, the power supply line 51a is in the direction opposite to the current direction of the power supply line 49a with respect to the hollow portion of the core 13a. The power supply line 51b is inserted so that a current flows in the direction opposite to the current direction of the power supply line 49b.

When the DC electric load device is composed of three DC electric motors, the two power lines connected to the power supply portion of the third DC electric motor are connected to the hollow portion of the core 13a. The power lines 49a and 49b of the first DC electric motor 45 are inserted in the same manner. Further, in the case where the DC electric load device is composed of four DC electric motors, the two power lines connected to the power supply portion of the fourth DC electric motor are connected to the hollow portion of the core 13a. The second DC electric motor 47 is inserted in the same manner as the power lines 51a and 51b.

Even when the DC electric load devices are the first and second DC electric motors 45 and 47, among the power lines 49a / 49b and 51a / 51b inserted in the hollow portion of the core 13a, for example, the power line 49a If 51a is positive (plus) and power lines 49b and 51b are negative (minus), and if the power lines 49a and 49b and 51a and 51b are not disconnected or the connection is normal, the wires 49a and 49b and 51a are connected. The detected current value detected by being excited by the detection coil 13b in the equilibrium state of the magnetic field generated by the current of 51b is the reference current value Iref. It becomes the following approximate “0”, and the DC power is continuously supplied to the first and second DC electric motors 45 and 47 to be operated in parallel.

On the contrary, when the power supply lines 49a / 49b, 51a / 51b are disconnected or poorly connected, the magnetic field generated by the currents of the electric wires 49a / 49b, 51a / 51b transitions to the non-equilibrium state and is excited by the detection coil 13b. The detected current value detected is the reference current value Iref. As described above, when the disconnection signal from the comparison circuit 13d transitions to ON (HIGH), the synchronous power supply of DC power to the first and second DC electric motors 45 and 47 is cut off, and the notification means is notified based on the disconnection signal. The 13e is operated to notify the operator of the power line abnormality.

In the first to third embodiments, an electric motor (three-phase AC electric motor, two-wire single-phase AC electric motor, DC electric motor) has been described as the electric load device, but the electric load device of the present invention has a high output. Either an electric magnet (electromagnetic solenoid) or an electric heater suitable for obtaining a predetermined high output by connecting multiple electric load devices with low output and the same rating in parallel instead of the electric load device and operating them in parallel. There may be.

1 Three-phase AC electric load system as an electric load system 3 Three-phase AC power supply as a power source 5, 7, 9 Three-phase electric motor as an electric load device 11 Switching means 13 Power line abnormality detecting means 13a Core 13b Detection coil 13c Amplifier 13d Comparison circuit 13e Notification means 15a-15c, 17a-17c Power supply lines U, V, W Power supply unit Iref. Reference current value 21 Single-phase AC electric load system as an electric load system 23 Two-wire single-phase AC power supply 25, 27 as a power source First and second single-phase AC electric motors 29a / 29b, 31a / 31b as an electric load device Power line 41 DC electric load system as an electric load system 43 DC power supply as a power source 45/47 First and second DC electric motors 49a / 49b, 51a / 51b as an electric load device Power supply lines A, B

Claims (11)

In an electric load system in which multiple electric load devices are connected in parallel to the power supply and power is supplied synchronously to each electric load device for parallel operation.
The current of the entire power supply line is detected by the power supply line abnormality detecting means based on the magnetic field generated by the current of the power supply line connected in parallel to each electric load device, and if the detected current value is less than or equal to the reference current value, each power supply line is detected. Is judged to be normal continuity and the synchronous power supply to each electric load device is continuously operated in parallel. On the other hand, if the above-mentioned detected current value is equal to or higher than the reference current value, one of the power supply lines is judged to be abnormal continuity. A method for detecting power line abnormalities in an electric load system that interrupts the synchronous power supply of AC power to each electric load device and stops parallel operation. In claim 1,
The power line abnormality detection means is a magnetic detection type power line abnormality detection method that detects the magnetic field generated by the current flowing through each power line inserted through the hollow part of the core and outputs the detection current. In claim 2,
The power line of each electric load device is inserted into the hollow part of the core so that the current directions are staggered, and the power line abnormality detection of the electric load system magnetically detects the current of the entire power line by the power line abnormality detection means. Method. In any of claims 1 to 3,
A power line abnormality detection method for an electric load system in which the power supply is a three-phase AC power supply whose phases are shifted by 120 degrees and the electric load device is a three-phase AC electric load device driven by the three-phase AC power. In claim 4,
In the hollow part of the core, the power lines of each three-phase AC electric load device have alternating current directions, and the one-phase power line of each three-phase AC electric load device has the current direction of the other two-phase power lines. A power line abnormality detection method for an electric load system that magnetically detects the current of the entire power line by inserting it in the opposite direction and using the power line abnormality detection means. In any of claims 1 to 3,
A power line abnormality detection method for an electric load system in which the power supply is a 2-wire single-phase AC power supply and the electric load device is a 2-wire single-phase AC electric load device driven by single-phase AC power. In claim 6,
An electric load system in which the power lines of each two-wire single-phase AC electric load device are inserted into the hollow part of the core so that the current directions are staggered, and the current of the entire power line is magnetically detected by the power line abnormality detecting means. Power line abnormality detection method. In any of claims 1 to 3,
A power line abnormality detection method for an electric load system in which the power source is a DC power source and the electric load device is a DC electric load device driven by DC power. In claim 8.
The power line of each DC electric load device is inserted into the hollow part of the core so that the current directions are staggered, and the power line abnormality of the electric load system that magnetically detects the current of the entire power line by the power line abnormality detecting means. Detection method. In any of claims 4 to 9,
The detection current value detected by the power line abnormality detecting means is less than or equal to the reference current value when the power line of the power supply and the power line of the electric load device are conducting in the normal state, and the power line of the power supply and the electric load. A method for detecting power line abnormalities in an electric load system that exceeds the reference current value when the power line of the device has poor continuity. In any of claims 1 to 10,
A power line abnormality detection method for electric load devices that activates the notification means to notify the power line abnormality when the detection current value is equal to or higher than the reference current value and the synchronous power supply to each electric load device is cut off.

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