JPH11329171A - Protective device for detecting blown fuse of high voltage device for temporary power transmission - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To open a trip type high-voltage switchgear by electrically detecting a blown fuse due to an overload / short-circuit accident or a mechanical shock when transporting or moving the temporary power transmission high-voltage device. Further, the present invention provides a protection device for detecting a blown fuse of a high-voltage device for temporary power transmission, which can achieve a reduction in size and weight and high reliability with a simple configuration. SOLUTION: The high voltage device for temporary power transmission has an opening / closing portion 103 and fuses 104a to 104c between a power supply side and a load side, and voltage sensors 107a to 108c for detecting voltages of respective phases are provided on both sides of the fuses. Connected. These voltage sensors include three fuse blown detection circuits 10A, 10B,
10C is connected. Each fuse blown detection circuit includes a phase comparison circuit 14 for detecting a different phase, and a NAND gate 16 for detecting the presence or absence of a detection voltage. Fuse blow detection circuit 1
When any of 0A to 10C determines that the fuse has blown, the OR circuit 20 opens the trip type high-voltage switch 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting and protecting a blown fuse of a high-voltage device for provisional power transmission, and more particularly to a provisional power transmission used for supplying power by provisional power transmission when a new power receiving facility is installed or repaired by a high-voltage customer. The present invention relates to a device for detecting and protecting a blown fuse in a high-voltage device.

2. Description of the Related Art In the case of supplying power by temporary transmission at the time of new installation or repair of a power receiving facility of a high voltage customer, in the event of an accident on the power receiving facility side, a temporary transmission power high voltage device is used to prevent the accident from spreading to the power side. Power is supplied. This temporary power transmission high-voltage device can be roughly classified according to its function.
rent and Ground relay) It consists of a switch and a switch with fuse. Specifically, it is configured to include a directional ground fault relay for detecting a ground fault, a trip type high voltage switch for shutting off a power supply side and a load side, and a switchgear. The switchgear is provided with a fuse for protecting the load by being blown by an overcurrent at the time of a short circuit accident, and a mechanism for mechanically detecting the blown fuse and opening the load side collectively. There are three types of accidents that can occur on the power receiving facility side: a ground fault, an overcurrent accident, and an accident in which a ground fault and an overcurrent accident occur simultaneously. For these accidents, the temporary power transmission high-voltage device must function effectively. The conventional high-voltage device for temporary power transmission opens a trip type high-voltage switch when a ground fault occurs on the power receiving equipment side during temporary power transmission, and mechanically disconnects the fuse in the case of a short-circuit accident. It has a function of detecting by means and opening the three phases on the load side collectively by a switchgear.

However, according to the conventional fuse blowout detection and protection device of the high voltage device for temporary power transmission, when a short-circuit accident occurs, the cutoff of the fuse is mechanically detected (for example, when a fuse blowout occurs). A mechanism is provided in the fuse body to project the notch to mechanically detect the projection of the notch.) The switch is driven to release the load from the power supply side, so that the structure is complicated and the size is increased. Since the temporary power transmission high-voltage device frequently changes its use place and is often transported and moved, the large-size temporary power transmission high-voltage device deteriorates workability and easily causes a failure. Therefore, an object of the present invention is to detect a blown fuse due to an overload / short circuit accident and a mechanical shock during transportation or movement of a temporary power transmission high-voltage device, and open the trip type high-voltage switch. Another object of the present invention is to provide a protection device for detecting a blown fuse of a high-voltage device for provisional power transmission, which can achieve a reduction in size and weight and high reliability with a simple configuration.

In order to achieve the above object, the present invention has, as a first feature, a high voltage switch provided between a power supply side and a load side to open and close a temporary transmission line, and A high-voltage device for temporary power transmission, which is equipped with a plurality of fuses inserted in each phase on the load side of the high-voltage switch and is used when performing temporary power transmission during construction such as new installation and repair of high-voltage customer power receiving equipment , A first and a second voltage detection sensor provided on both sides of the plurality of fuses and detecting a voltage of each phase;
An out-of-phase state is detected from the phase difference between the detection voltages between the first and second voltage detection sensors, and the voltage of at least one of the voltages detected by the first and second voltage detection sensors is equal to or less than a predetermined value. A plurality of blown fuse detection circuits that determine the cutoff of the fuse by being, and a control unit that opens the high-voltage switch when any of the plurality of blown fuse detection circuits determines the cutoff of the fuse,
The present invention provides a device for detecting and protecting a blown fuse of a high-voltage device for provisional power transmission. Further, in order to achieve the above object, the present invention provides, as a second feature, a high-voltage switch provided between a power supply side and a load side to open and close a temporary transmission line, and a high-voltage switch on the load side of the high-voltage switch. A plurality of fuses inserted in each phase, a plurality of current transformers provided in each phase preceding the high-voltage switch, and a zero-phase current transformer provided between the high-voltage switch and the fuse. In the high-voltage device for temporary power transmission used when performing temporary power transmission in construction such as new construction and repair of high-voltage customer power receiving equipment, the voltage of each phase is provided on both sides of the plurality of fuses. First and second to detect
A voltage detection sensor, a third voltage detection sensor provided on the power supply side of the high-voltage switch to detect a voltage of each phase, and a zero-phase current detected by the zero-phase current transformer and the plurality of current transformers. A directional ground fault relay unit that detects a ground fault based on a phase of a current and a phase of a zero-phase voltage detected by the third voltage detection sensor, and a detection voltage between the first and second voltage detection sensors. An out-of-phase state is detected from the phase difference, and at least one of the voltages detected by the first and second voltage detection sensors is detected.
A fuse blown detection circuit that determines whether or not the fuse is cut off when a phase voltage is equal to or less than a predetermined value, and the high-voltage switch when an output signal is generated in the directional ground fault relay unit or the fuse blown detection circuit. And a control device for opening the fuse.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of a device for detecting and protecting a blown fuse of a high-voltage device for provisional power transmission according to the present invention. The blown fuse detection and protection device 1 is connected to a trip type AC high-voltage load switch (hereinafter, referred to as a “trip-type high-voltage switch”) 100 that is a component of the high-voltage device for temporary power transmission. The blown fuse detection and protection device 1 includes an A-phase blown-blow detection circuit 10A, a B-phase blown-blow detection circuit 10B, and a C-phase blown-blow that detect a phase difference and a voltage state based on a detection signal from the trip type high-voltage switch 100. A detection circuit 10C, and an OR circuit 2 that performs an OR operation on signals output from the fuse blown detection circuits of the three phases.
0 (control means) and an LED (light emitting diode) 30 which is turned on / off in accordance with the output of the OR circuit 20. The output of the OR circuit 20 is applied as a control command 40 (switch trip signal) to the trip coil 105 of the trip type high-voltage switch 100. The A phase fuse blown detection circuit 10A, the B phase fuse blown detection circuit 10B, and the C phase fuse blown detection circuit 10C have the same configuration,
FIG. 1 shows an internal circuit only for the A-phase fuse blown detection circuit 10A. The trip type high-voltage switch 100 corresponds to three phases (A-phase, B-phase, and C-phase).
Between the power supply side and the load side terminal 102 in order from the power supply side.
03, the fuses 104a, 104b, 104c are inserted and connected. The opening / closing section 103 includes a trip coil 10 that is excited by an output from the blown fuse detection and protection device 1.
5, an armature 106a that is operated by the trip coil 105, and an operating member 106b that opens and closes the opening and closing unit 103 in conjunction with the operation of the armature 106a. Fuses 104a, 104b,
Voltage detection sensors 107a (PD1A), 107b (PD1B), 107 are provided between each phase on the power supply side of 104c and the ground.
c (PD1C) is connected. Further, the fuse 10
The voltage detection sensors 108a (PD2A), 108b are connected between the respective phases on the load side of 4a, 104b, 104c and the ground.
(PD2B) and 108c (PD2C) are connected. Voltage detection sensors 107a, 107b, 107c, 1
08a, 108b, and 108c form a part of the blown fuse detection and protection device 1. However, since the lead wire cannot be routed from the trip type high-voltage switch 100 to the blown fuse detection and protection device 1 at a high voltage. , Is provided in the trip type high-voltage switch 100. Each of these voltage detection sensors is configured by connecting two capacitors in series, and detects a phase voltage divided by a capacitance ratio. Each output of the voltage detection sensors 107a, 107b, 107c is
9 and similarly output voltage detection sensors 108a, 108
Outputs b and 108c are also output to the signal line 110. Next, the configuration of the A-phase fuse blown detection circuit 10A will be described. An A / D converter 12a and a rectangular wave converter 13a are connected in parallel to the filter 11a connected to the signal line 109, and an A / D converter is connected to the filter 11b connected to the signal line 110.
The D converter 12b and the rectangular wave converter 13b are connected in parallel. The square wave converters 13a and 13b include a phase comparator 1
4 are connected. Also, the A / D converters 12a, 12
A weighting circuit 15 is connected to b, and a NAND (NAND) gate 16 is connected to the weighting circuit 15. An AND gate 17 is connected to the output of the NAND gate 16 and the output of the phase comparison circuit 14. The filters 11a and 11b are connected to the 5
Frequency components other than 0 Hz or 60 Hz are removed. The rectangular wave converters 13a and 13b generate a rectangular wave from the sine wave signal. The phase comparison circuit 14 includes a rectangular wave converter 13a,
The phase difference is measured from the time difference until the two rectangular waves output from 13b rise. The weighting circuit 15
Each of the digital values from the / D converters 12a and 12b is weighted and converted to a ground voltage. Then, the converted value is compared with a preset reference value (for example, の of the ground voltage), and if the converted value exceeds the reference value, it is determined that a voltage appears on the detection unit of the voltage detection sensor. The NAND gate 16 is at the "L" level when the two outputs of the weighting circuit 15 are at the "H" level at the same time, and outputs the "H" level at other times. In the above configuration, operations in Cases 1 to 5 will be described. [Case 1] The opening / closing section 103 is closed and the fuse 1
If no fuse blowout has occurred in the voltage detection sensors 104a, 104b, and 104c, the voltage detection sensors 107a to 107c and 10c
During 8a to 108c, three-phase voltages having the same phase and no phase difference are detected and output to the signal lines 109 and 110. As a result, the A-phase fuse blown detection circuit 10A, the B-phase fuse blown detection circuit 10B, and the C-phase fuse blown detection circuit 10A
Both output signals of C become "L" level, and the OR circuit 20
Is at the "L" level, the LED 30 remains off, and the control command 40 is not applied to the trip coil 105. [Case 2] When the switching unit 103 is open (switch open), the fuses 104a, 104b, and 104c are not blown and there is no voltage on the load side, the filters 11a, 1
No output signal is generated from 1b, the AND gate 17 does not satisfy the AND condition, and no output voltage is generated in the A-phase fuse blown detection circuit 10A. Similarly, no output voltage is generated in the B-phase fuse blown detection circuit 10B and the C-phase fuse blown detection circuit 10C. As a result, the OR logic is not established in the OR circuit 20, the LED 30 remains off, and the opening / closing section 10
3 remains open. [Case 3] The switch 103 is open (switch open), all of the fuses 104a, 104b, and 104c are normal, and for example, a generator is connected to the load. When there is a voltage, the voltage detection sensors 108a, 108b, 108c and the voltage detection sensor 10
Detection voltages are generated at 7a, 107b and 107c. In the A-phase fuse blown detection circuit 10A, the filter 11
Since a signal is output to each of a and 11b, the phase comparison circuit 14 cannot detect the phase difference, and its output becomes the “L” level. Since the A / D converters 12b and 12b also output signals respectively, no voltage difference occurs, and the output of the NAND gate 16 whose two inputs are both at the “H” level is “L”.
Become a level. As a result, the AND gate 17 does not establish AND logic, and no output signal is generated from the A-phase fuse blown detection circuit 10A. B-phase fuse blown detection circuit 10
Since the B and C phase fuse blown detection circuits 10C operate in exactly the same manner as the A phase fuse blown detection circuit 10A, no output signals are generated from the B phase fuse blown detection circuits 10B and 10C. Therefore, the OR circuit 20 has all three inputs at the “L” level, the output signal remains at the “L” level, the LED 30 remains off, and the control command 40 is not output to the trip coil 105. [Case 4] Under the condition of Case 3, when the fuse 104a is blown, no detection voltage is generated at PD1A of the voltage detection sensor 107a, and a detection voltage is generated at PD1B and PD1C. Further, the voltage detection sensors 108a, 108b,
A detection voltage is also generated in each of 108c. Therefore, as described in Case 3, the output signals of the B-phase fuse blown detection circuit 10B and the C-phase fuse blown detection circuit 10C remain at the “L” level, but the A-phase fuse blown detection circuit 10A operates differently. do. That is, no voltage is generated in the rectangular wave converter 13a, and only a voltage is generated in the rectangular wave converter 13b. Therefore, the phase comparison circuit 14 generates an output signal of "H" level. On the other hand, no output is generated in the A / D converter 12a, and an output is generated only in the A / D converter 12b. As a result, in the weighting circuit 15, an output voltage is generated at one output terminal and no output voltage is generated at the other output terminal. For this reason, one of the inputs of the NAND gate 16 becomes “H” level and the other becomes “L” level, and the output of the NAND gate 16 becomes “H” level. AND gate 17
Output is "H" because both inputs are at "H" level.
Become a level. In the OR circuit 20, the output of the A-phase fuse blown detection circuit 10A is "H" level, the output of the B-phase fuse blown detection circuit 10B is "L" level, and the output of the C-phase fuse blown detection circuit 10C is "L" level. Because of this, the OR logic is established, and the output becomes “H” level. Therefore, the LED 30 is turned on to warn of "blown fuse (blown fuse)" and a control command 40 is output. However, in this state, since the opening / closing unit 103 has already been opened, that state is maintained. Although the fuse 104a has been described, the operation is the same even when the other fuses 104b and 104c are cut off. In case 3, if all of the fuses 104a, 104b, and 104c are blown, the A-phase fuse blown detection circuit 10A, the B-phase fuse blown detection circuit 10B, and the C-phase fuse blown detection circuit 1
The output of the OR circuit 20 becomes "H" level, and the OR circuit 20
Operates to turn on the LED 30 and output the control command 40. As described above, since the final output is obtained through the OR circuit 20, if one of the fuses 104 is cut, the same operation is performed regardless of whether two or three fuses are cut. [Case 5] Fuse 104 with opening / closing section 103 closed
a, 104b, or 104c, for example, when the fuse 104a is blown, the voltage detection sensors 107a, 107
Although a detection voltage is generated in each of 7b, 107c, 108b, and 108c, no detection voltage is generated in the voltage detection sensor 108a. Therefore, the rectangular wave converter 13a
, And no output is generated in the rectangular wave converter 13b, so that the output of the phase comparison circuit 14 becomes "H" level.
Further, since an output is generated in the A / D converter 12a and no output is generated in the A / D converter 12b, one of the inputs of the NAND gate 16 becomes "H" level and the other becomes "L" level,
The output of the NAND gate 16 becomes "H" level. Since both the NAND gate 16 and the phase comparison circuit 14 output “H” level, the output of the AND gate 17 becomes “H” level. At this time, the B-phase fuse blown detection circuit 10
Although the outputs of the B and C phase fuse blown detection circuits 10C are both at the "L" level, the output of the AND gate 17 is at the "H" level, so that the OR logic is established in the OR circuit 20, and the output is "H". Become a level. Therefore, LE
D30 lights up to warn of "blown fuse". At the same time, the control command 40 is output, so that the trip coil 1
05 is energized, and the trip type high-voltage switch 100 is tripped (the switch 103 is opened). Next, as described above, the AND condition of the phase difference and the presence or absence of the voltage is
The reason taken in Section 2 will be explained. When the switching unit 103 is closed, a sneak voltage is generated depending on the state of the load, and even if the fuse is blown, the detection voltage may be higher than a normal voltage value. Therefore, if the blowout of the fuse is determined only based on the presence or absence of the detection voltage, it may be determined that the fuse is not blown even though the fuse is actually blown. In the case of a blown fuse, the phase of the wraparound voltage of that phase becomes a phase value obtained by combining the other phases, so that the phase difference from the opposite end where the voltage is generated becomes 180 ° ± 70 °. Therefore, in the present invention, the phase difference is detected, and if the phase of the sneak voltage is ± 45 ° or more, the phases are determined to be out of phase, and the fuse blow is determined when the two conditions of the voltage detection are satisfied simultaneously with the detection of the phase difference. . FIG. 2 shows a second embodiment of the device for detecting and protecting a blown fuse according to the present invention. In FIG. 2, the same reference numerals are used for members having the same or the same functions as the members shown in FIG. 1, and duplicate descriptions are omitted. The feature of the present embodiment resides in that an SOG function is provided. The delay function priority processing is performed when a short-circuit fault occurs, and the fuse blown trip control is not performed when the energy storage trip is stored. That is, the interruption of the short-circuit current is not performed. In order to provide the SOG function, the trip type high-voltage switch 100 has a voltage detection sensor 111a (PD3A), 1 in addition to the configuration of FIG.
11b (PD3B), 111c (PD3C), current transformers (CT) 112a, 112b, 112c, and zero-phase current transformer (ZCT) 113 are provided. Voltage detection sensor 111
a, 111b, and 111c are provided between the power supply terminal 101 and the ground. Current transformers (CT) 112a, 112b,
Reference numeral 112c denotes A between the power supply terminal 101 and the opening / closing unit 103,
Zero phase current transformer (ZCT) 11 attached to each phase B and C
Reference numeral 3 is attached to each of the phases A, B, and C between the opening / closing section 103 and the fuse 104. Voltage detection sensors 111a, 1
Like the other voltage detection sensors, 11b and 111c form a part of the blown fuse detection and protection device 1, but are drawn from the trip type high-voltage switch 100 to the blown fuse detection and protection device 1 at a high voltage. Since it cannot be routed, it is provided in the trip type high-voltage switch 100. Also,
The fuse blown detection protection device 1 includes a fuse blown detection circuit 50 including three circuits of the fuse blown detection circuits 10A, 10B, and 10C shown in FIG. 1 and an LED 30, a directional ground fault relay unit 60, and a phase detector. A circuit 70, an OR gate 80 (control means), and an LED 90 are provided. The directional ground fault relay unit 60 includes the voltage detection sensors 111a, 111
b, 111c, current transformers 112a, 112b, 112c,
And the output of the zero-phase current transformer 113. In the configuration of FIG. 2, the operation of the blown fuse detection circuit 50 includes the A-phase blown-blow detection circuit 10A, the B-phase blown-blow detection circuit 10B, and the C-phase blown-blow detection circuit 1 of FIG.
Since it is as described for 0C, duplicate description is omitted. When an overcurrent fault on the load side is detected by the current transformers 112a, 112b, 112c, the occurrence of the overcurrent fault is stored in a storage means (not shown), and the LED 30 is turned on.
At this time, a circuit breaker (not shown) on the power supply side operates to stop the high voltage distribution line. If the control power supply is lost due to a power failure in the high-voltage distribution line, for example, after 0.5 seconds or more, the trip type high-voltage switch 100 is automatically opened.
In the event of a ground fault, the phase of the zero-phase current detected by the zero-phase current transformer 113 and the current transformers 112a, 112b, 112c and the voltage detection sensors 107a, 107b, 107c
The directional ground fault relay unit 60 determines the direction of the ground fault current based on the phase of the zero-sequence voltage detected in step (1). When it is determined that the load side ground fault has occurred, the detection signal (“H” level voltage) indicating “there is a ground fault” is output to the OR gate 80.
Output to The OR gate 80 changes the output to "H" level, applies the control command 40 to the trip coil 105, and opens the trip type high-voltage switch 100. The phase detection circuit 70
The detection voltages of the voltage detection sensors 111a, 111b, 111c and the detection voltages of the voltage detection sensors 108a, 108b, 108c are compared in the same phase, and when different phases are detected on the power supply side and the load side from the phase difference, The LED 90 is turned on to warn of the "out-of-phase" condition. Since the configuration of FIG. 2 has the SOG function as described above, when the ground fault and the overcurrent accident overlap, the operation of the overcurrent relay has priority. Therefore, after operation of the circuit breaker,
After 0.5 seconds or more, the trip type high-voltage switch 100 is opened. In addition, when the energy storage trip is stored, the fuse blown trip control is not performed, and thereby the short-circuit current is not interrupted. For this reason, the blown fuse detection time is set to be longer than the ground fault detection time so that the ground fault detection process can be given priority over the blown fuse detection process without fail. In each of the above embodiments, one LED 30 is connected to the OR circuit 2.
0, and the blown fuse detection circuits 10A, 10B, 1
It is not known which of 0C caused the blown fuse. However, the blown fuse detection circuits 10A, 10B,
If the configuration is such that the output terminals are connected to the respective output terminals of 10C, it is possible to know in which phase the fuse has blown. In the above description, the trip type high-voltage switch has been described as an example.
The invention is not limited to this type. Also,
The present invention can be applied not only to three phases but also to other cases such as a single phase.

As described above, according to the present invention, according to the present invention, the out-of-phase state is detected from the phase difference between the phase voltages detected from both sides of the fuse by the voltage detection sensor. A plurality of blown fuse detection circuits for determining a blown fuse when the voltage detected by the voltage detection sensor is equal to or lower than a predetermined value; and a high-voltage open / close circuit when any of the plurality of blown fuse detection circuits determines a blown fuse. The high-voltage switch can be opened by electrically detecting a blown fuse due to a short-circuit accident, and the size and weight of the temporary power transmission high-voltage device can be reduced with a simple configuration. High reliability can be achieved. Further, a directional ground fault relay unit that detects the time of a ground fault based on the phase of the zero-phase current and the phase of the zero-phase voltage, and determines whether the fuse has blown when the voltage detected by the voltage detection sensor is equal to or less than a predetermined value. By providing a configuration including a plurality of fuse blown detection circuits, and control means for opening the high voltage switch when an output signal is generated in any of the directional ground fault relay section or the fuse blown detection circuit. In addition, priority can be given to the delay function at the time of short-circuit failure, and the safety of the system can be improved. In addition, at the time of storing the energy accumulation trip,
Fuse blow trip control can be omitted.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a device for detecting and protecting a blown fuse of a high-voltage device for provisional power transmission according to the present invention.

FIG. 2 shows a second embodiment of the protection device for detecting a blown fuse according to the present invention.
FIG. 3 is a circuit diagram showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuse blow detection protection device 10A A phase fuse blow detection circuit 10B B phase fuse blow detection circuit 10C C phase fuse blow detection circuit 11a, 11b Filter 12a, 12b A / D converter 13a, 13b Square wave converter 14 Phase comparison circuit Reference Signs List 15 weighting circuit 16 NAND gate 17 AND gate 20, 80 OR circuit 30 LED 50 fuse blown detection circuit 60 directional ground fault relay unit 100 trip type high voltage switch 103 switching unit 104a, 104b, 104c fuse 105 trip coil 107a, 107b, 107c Voltage detection sensor 108a, 108b, 108c Voltage detection sensor 111a, 111b, 111c Voltage detection sensor 112a, 112b, 112c Current transformer 113 Zero-phase current transformer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuhiro Taniguchi 5-2-1 Ebara, Shinagawa-ku, Tokyo Saneisha Manufacturing Co., Ltd.

Claims (4)

[Claims] 1. A high-voltage switch provided between a power supply side and a load side to open and close a temporary transmission line, and a plurality of fuses inserted into each phase on the load side of the high-voltage switch. ,
In a high-voltage device for temporary power transmission used when performing temporary power transmission in construction such as new installation and repair of a high-voltage customer power receiving facility, first and second power supply devices provided on both sides of the plurality of fuses and detecting a voltage of each phase. And a second voltage detection sensor, wherein a different phase state is detected from a phase difference between detection voltages between the first and second voltage detection sensors, and at least one of the voltages detected by the first and second voltage detection sensors. A plurality of blown fuse detection circuits that determine the blowout of the fuse by determining that the phase voltage is equal to or less than a predetermined value; and the high-voltage switch when any of the plurality of blown fuse detection circuits determines the blowout of the fuse. And a control means for opening the fuse. A protection device for detecting a blown fuse of a high-voltage device for provisional power transmission. 2. The high voltage device for provisional power transmission according to claim 1, wherein said fuse blown detection circuit determines whether or not the voltage is equal to or lower than said predetermined value based on a half of a ground voltage. Fuse blow detection protection device. 3. The fuse blown detection circuit is characterized in that the out-of-phase detection is performed when a phase difference between detection voltages between the first and second voltage detection sensors is ± 45 ° or more. The protection device for detecting a blown fuse of a high-voltage device for provisional power transmission according to claim 1. 4. A high-voltage switch provided between a power supply side and a load side for opening and closing a temporary transmission line, a plurality of fuses inserted in each phase of the high-voltage switch on a load side, and the high-voltage switch A plurality of current transformers provided in each phase at the preceding stage, and a zero-phase current transformer provided between the high-voltage switch and the fuse. In a high-voltage device for temporary power transmission used when performing temporary power transmission in construction work, a first and a second voltage detection sensor provided on both sides of the plurality of fuses and detecting a voltage of each phase; A third voltage detection sensor that is provided on the power supply side of the switch and detects a voltage of each phase; and a phase of the zero-phase current detected by the zero-phase current transformer and the plurality of current transformers; Directionality to detect ground fault based on phase of zero-sequence voltage detected by voltage detection sensor An out-of-phase state is detected from a phase difference between detection voltages between the ground fault relay unit and the first and second voltage detection sensors, and at least one phase of a voltage detected by the first and second voltage detection sensors A fuse cut-off detection circuit that determines that the fuse is cut off when the voltage of the fuse is equal to or less than a predetermined value, and opens the high-voltage switch when an output signal is generated in the directional ground fault relay unit or the fuse cut-off detection circuit. And a control device for performing a blow-out detection and protection device of the high-voltage device for provisional power transmission.