An arc protection system used in substations

Abstract

The present invention provides an arc protection system for use in a substation. The arc protection system comprises at least two main control systems, each of which is connected to a first arc detection unit, a second arc detection unit, and a power module. The main control system protects at least one switch cabinet of the substation. The first arc detection unit and the second arc detection unit directly transmit the detected arc light to the main control system. The main control system outputs a trip signal to a circuit breaker based on the received arc light. The circuit breaker is arranged between a power supply incoming line and a busbar of the substation. The arc protection system for use in a substation provided by the present invention adopts both arc light and current dual judgment criteria. When an arc light occurs in the substation, the system trips safely and quickly, cuts off the arc light, protects operators from injury, reduces the degree of property loss, and prevents large-scale power outages caused by misjudgment.

Description

Technical Field

[0001] The present invention relates to the field of arc protection equipment, and in particular to an arc protection system applied to a transformer substation. Background Art

[0002] A substation is a place where voltage is changed. To transmit electricity generated by a power plant to distant locations, the voltage must be stepped up to high voltage. The voltage is then stepped down as needed near the user. This voltage step-up and step-down process is performed by the substation. The main equipment in a substation is switches and transformers. Substations generally refer to step-down substations with voltage levels below 110 kV. Substations include both step-up and step-down substations at various voltage levels. A substation is a power facility that transforms voltage, receives and distributes electricity, controls the flow of power, and adjusts voltage within the power system. It connects power grids at different voltage levels through its transformers. In certain environments, a substation performs the AC-DC-AC conversion process, such as in submarine transmission cables and long-distance transmission. Some use high-voltage direct current (HVDC) transmission and transformation. DC transmission overcomes the capacitive losses associated with AC transmission and offers energy-saving benefits. However, substations are prone to arcing during operation.

[0003] The arc protection system can protect operators from injury and reduce property losses when an arc fault occurs in the switch cabinet of the substation. When an arc occurs, the arc bursts out at a speed of 300m / s, destroying any objects in the way. As long as the system is powered on, the arc will continue to exist. The arc protection system can reduce the hazards of arc light. In the switch cabinet drawer, the arc can quickly reach 3m within 10ms. The arc protection system outputs a trip signal in an extremely short time, which can protect the safety of operators even during installation or maintenance. However, the existing arc protection system only has one criterion, which can easily lead to misjudgment and cause large-scale power outages. Summary of the Invention

[0004] In view of the above problems, the present invention provides an arc protection system for use in a substation, wherein the arc protection system includes at least two main control systems, each of which is connected to a first arc detection unit, a second arc detection unit, and a power module;

[0005] The main control system protects at least one switch cabinet of the substation, and the first arc detection unit and the second arc detection unit directly transmit the detected arc to the main control system;

[0006] The main control system outputs a trip signal to the circuit breaker based on the received arc light. The circuit breaker is set between the power supply line and the busbar of the substation.

[0007] Furthermore, the main control system is arranged on the first incoming cabinet panel, the first arc detection unit is arranged on the second incoming cabinet panel, and the second arc detection unit is arranged on the third incoming cabinet panel.

[0008] Furthermore, the arc protection system also includes a temperature measuring probe and a pressure measuring probe connected to the main control system. The temperature measuring probe is connected to the main control system through an arc unit. The temperature measuring probe includes an optical fiber temperature measuring probe and / or a distributed optical fiber linear temperature detector; optical signals are transmitted between the arc unit and the temperature measuring probe through optical fibers; optical signals are transmitted between the arc unit and the first arc detection unit and the second arc detection unit through temperature-sensitive optical fibers.

[0009] Furthermore, the main control system also includes a tripping control circuit, which provides two output tripping signals for each circuit breaker, one of which is directly connected to the circuit breaker circuit, and the other enters the relay connected to the circuit breaker tripping circuit. The first arc detection unit inputs the alarm signal into the main control system and outputs the tripping signal from the first path at the same time. The second arc detection unit inputs the alarm signal into the main control system and outputs the tripping signal from the first path and the second path respectively.

[0010] Furthermore, the protection system also includes a temperature judgment circuit. The temperature measuring probe is a distributed optical fiber linear temperature detector, and the distributed optical fiber linear temperature detector is bundled on the outer surface of the electrical cabinet. The temperature judgment circuit is implemented by the following steps:

[0011] S1: Preset the coordinates of the sampling points of the distributed optical fiber linear temperature detector on the electrical cabinet, collect the temperature signal T of each sampling point, and compare all the current temperature signals T with the temperature threshold T 阈 Compare and judge whether T exceeds T 阈 The number of sampling points P, when P < 3, no processing is performed, when P ≥ 3, step S2 is performed;

[0012] S2: Collect and obtain the coordinates of the corresponding P sampling points, connect any three coordinates to obtain at least one triangle, and determine whether the maximum angle of the triangle is less than 150°. If so, calculate the area S of the triangle and compare S with the area threshold S. 阈 If S<S threshold, proceed to step S3;

[0013] S3: The main control system sends a trip signal to the circuit breaker.

[0014] Furthermore, the arc protection system further includes a hybrid criterion circuit, which is implemented by the following steps:

[0015] Step S1 also includes: presetting the coordinates of the sampling points of the distributed optical fiber linear temperature detector on the electrical cabinet, collecting the temperature signal T of each sampling point, and comparing all the current temperature signals T with the temperature threshold T.阈 Compare and judge whether T exceeds T 阈 The number of sampling points P, when 1≤P<3, proceed to step S4;

[0016] S4: Repeatedly detect the temperature T of P sampling points and determine whether the temperature T still exceeds T 阈 , if yes, proceed to step S3.

[0017] Furthermore, step S4 includes: repeatedly detecting the temperature T of P sampling points, and determining whether the temperature T still exceeds T 阈 If not, other parameters are tested and instructions are sent to the main control system according to the test results.

[0018] Furthermore, detecting other parameters and sending instructions to the main control system according to the detection results includes the following steps:

[0019] S41: Determine whether arc light is detected. If yes, proceed to step S3; if not, do nothing.

[0020] S42: Determine whether the current signal exceeds the current threshold, if yes, proceed to step S3, if no, do nothing;

[0021] S43: Determine whether the voltage signal exceeds the voltage threshold. If yes, proceed to step S3; if no, do nothing.

[0022] Furthermore, the distance between two adjacent sampling points is between 5 cm and 20 cm.

[0023] Furthermore, the voltage threshold is (110-120)% of the rated voltage effective value, the current threshold is (120-200)% of the effective value of the current power frequency signal and the (3-25)th odd harmonic, and the light sensitivity of the arc detection unit and the arc unit is 30,000 lux.

[0024] The present invention also provides the application of the above arc protection system in power supply bureau substations and large mining enterprise substations.

[0025] The beneficial effects of the present invention are as follows:

[0026] The arc protection system provided by the present invention for use in substations adopts both arc and current dual criteria, and can safely and quickly trip when an arc occurs in the substation, cutting off the arc, protecting operators from injury, reducing the degree of property loss, and preventing large-scale power outages caused by misjudgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the wiring diagram of the arc protection system used in substations;

[0028] Figure 2 This is a schematic diagram of the address setting of the arc unit;

[0029] Figure 3 It is the schematic diagram of the current unit port;

[0030] Figure 4 This is a schematic diagram of the current unit dial;

[0031] Figure 5 This is the port diagram of the power module;

[0032] Figure 6 Schematic diagram of the structure of the arc detection unit;

[0033] Figure 7 This is a schematic diagram of sensitivity adjustment of the arc detection unit;

[0034] Figure 8 This is a structural diagram of the arc protection system used in substations;

[0035] Figure 9 This is a structural diagram of the distributed optical fiber linear temperature detector bundled on the outer surface of the switch cabinet;

[0036] Figure 10 It is a typical example of power distribution for power supply bureau substations and large factories and mines.

[0037] Among them, 100-electrical cabinet, 200-sampling point, 300-circle (area threshold is the area of the circle), 400-triangle. DETAILED DESCRIPTION

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and the following examples.

[0039] In some embodiments, an arc protection system for a substation is provided. Figure 1 As shown, the arc protection system includes two main control systems, each of which is connected to a first arc detection unit, a second arc detection unit, and a power supply module;

[0040] The main control system protects at least one switch cabinet of the substation, and the first arc detection unit and the second arc detection unit directly transmit the detected arc to the main control system;

[0041] The main control system outputs a trip signal to the circuit breaker based on the received arc light. The circuit breaker is set between the power supply line and the busbar of the substation;

[0042] The main control system is arranged on the first incoming line cabinet panel, the first arc detection unit is arranged on the second incoming line cabinet panel, and the second arc detection unit is arranged on the third incoming line cabinet panel.

[0043] This embodiment reduces the incidence of misjudgment by setting the arc light and current dual judgment criteria.

[0044] When the main control system lacks arc measurement ports, arc units must be used. Using arc units can also save on optical fiber costs because they can be placed near the location requiring protection. Only one optical fiber is needed to connect one arc unit to another current unit, arc unit, or main control system. A potentiometer is located on the arc unit panel, which adjusts the light sensitivity. Once calibrated, the information is transmitted to the next current unit, arc unit, or to the main control system. The potentiometer simultaneously calibrates all arc input signals in the arc unit. Once the optical fiber required to connect the arc unit is installed, the potentiometer must be adjusted. The arc unit can replace some optical cables. In this case, the protection system can always accurately identify detection unit signals outside the set light sensitivity range. To ensure that the main control system can quickly and promptly identify the arc fault address of each individual unit, the unit address should be set in the arc unit. The addresses of arc units, current units, voltage probes, and temperature probes in the following embodiments within the same main control system must be unique. The pre-set addresses facilitate the work of operators and remote controllers but do not affect the tripping function. Figure 2 As shown, the address can be set using the DIP switch inside the unit. Figure 2 As shown in the settings, when the protection system changes the address during operation, the main control system will automatically find the correct address. Please note that if the original address cannot be found, the main control system will notify you. Similarly, the binary value plus 1 is the number.

[0045] The current unit is used to ensure the operability of the tripping logic of the protection system under different operating conditions. By using the current unit, the tripping logic in the arc protection system can be diversified and have more options. Different current sampling values can be defined by the different positions of the dip switch in the measurement circuit. The current unit can adapt to the secondary currents of 5A, 2A and 1A in the system to be connected to this current unit. In order to ensure these connections, the state of the dip switch needs to be set in the current unit. Different states of the dip switch correspond to different current sampling values. However, these secondary current terminals are directly connected to the terminals of the current unit. The overcurrent setting range is 50~500%*In. The current measurement data of the switchgear is connected to the terminals behind the current unit, such as Figure 3 As shown, terminals 1-2 correspond to L1, terminals 3-4 correspond to L2, and terminals 5-6 correspond to L3. If 5A current is connected, Figure 4As shown, the status of the DIP switch is that the three positions 1, 3, and 5 are kept down, and the three positions 2, 4, and 6 are kept horizontal; if the current is 2A, the status of the DIP switch is that the three positions 1, 3, and 5 are kept horizontal, and the three positions 2, 4, and 6 are kept underwater; if the current is 1A, the status of the DIP switch is that the three positions 1, 3, and 5 are kept horizontal, and the three positions 2, 4, and 6 are kept underwater; if the current is 1A, the status of the DIP switch is that the three positions 1, 2, 3, 4, 5, and 6 are all kept horizontal; the grounding terminal must be firmly connected, the data output cable is connected to the "Dataout" port (to the main control system or arc unit), the corresponding trip signal output optical fiber is connected to the "tripout" port, the data transmission cable connected from other arc units or current units is connected to the "Datain" port, and the trip signal input optical fiber is connected to the "tripin" port; the arc protection system has an independent power supply, which supplies power to the main control system, and the main control system provides working voltage to the arc unit and current unit. The connection of the power supply module is as shown in the figure. Figure 5 As shown, L and N are connected to the external 220V AC power supply, +V and -V are connected to the power port of the main control system, among which +V is connected to the +12VDC of the main control system, and -V is connected to the -12VDC- of the main control system. +V and -V must be connected to the main control system ports accurately, otherwise it will cause system damage and other malfunctions.

[0046] Arc detection unit such as Figure 6 As shown, the arc detection unit can cover a much larger range than its end. Since there are no moving or live parts, the detection unit is very easy to install, will not cause any malfunction, and does not require any maintenance. The sensitivity of the arc protection system can be adjusted in the arc unit and the main control system. This sensitivity is affected by the arc detection unit and the length of the optical cable, such as Figure 7As shown, the sensitivity can be adjusted between 10 and 50k lux. The measurement can be performed using an optical cable, a 1000W work light and a MetzMecablitz20B5 flashlight. During the measurement, the ambient light illumination is 300 lux. The arc detection unit should be installed in the area to be protected in the switch cabinet. The detection unit does not need to be aimed at the protected point because the detection range of the detection unit is circular and can cover the rear of the detection unit. In the open busbar compartment, in order to achieve the required protection level, the detection unit is installed at an interval of 6 to 7m. In the medium voltage part, all isolation Different arc detection units should be used to protect different spaces separately. In the low-voltage part, at least the busbar and incoming switch interval should be protected. The detection unit is inserted into the 8mm hole and fixed with a push-pull connector. The detection unit can also be installed on the mounting bracket of the arc detection unit. The specific method is to insert the detection unit into the 8mm hole on the fixed bracket, and then fix it with a push-pull connector. Finally, fix the fixed bracket with the detection unit in the appropriate position in the cabinet to complete the installation and fixation of the detection unit. The fixed bracket with the detection unit can also be installed on the concrete surface that cannot be attached according to actual needs.

[0047] In certain embodiments, as Figure 8 As shown, the arc protection system also includes a temperature measuring probe and a pressure measuring probe connected to the main control system. The temperature measuring probe is connected to the main control system through an arc unit. The temperature measuring probe includes an optical fiber temperature measuring probe and / or a distributed optical fiber linear temperature detector; optical signals are transmitted between the arc unit and the temperature measuring probe through optical fibers; optical signals are transmitted between the arc unit and the first arc detection unit and the second arc detection unit through temperature-sensitive optical fibers.

[0048] This embodiment adds two more criteria on the basis of the dual criteria by adding a temperature measuring probe and a pressure measuring probe, which can further prevent misjudgment.

[0049] In some embodiments, the main control system also includes a trip control circuit, which provides two output trip signals for each circuit breaker, one of which is directly connected to the circuit breaker circuit, and the other enters the relay connected to the circuit breaker trip circuit. The first arc detection unit inputs the alarm signal into the main control system and outputs the trip signal from the first path at the same time. The second arc detection unit inputs the alarm signal into the main control system and outputs the trip signal from the first path and the second path respectively.

[0050] Among them, such as Figure 1 As shown, when an arc occurs and the alarm signal is input to L2, the Triac1 and Triac4 ports are output simultaneously.

[0051] When an arc occurs, the alarm signal is input to L1, and Triac2, Triac3, Relay2, and Relay3 are output simultaneously;

[0052] #if 1

[0053] if(Line1_light)

[0054] {

[0055] ucQ_OutValue|=0x4; / / Fast 1

[0056] / / ucQ_OutValue|=0x8; / / Fast 2

[0057] / / ucQ_OutValue|=0x2; / / Fast 3

[0058] ucQ_OutValue|=0x1; / / Fast 4

[0059] ucS_OutValue|=0x1; / / slow speed 1

[0060] / / ucS_OutValue|=0x2; / / slow speed 2

[0061] / / ucS_OutValue|=0x4; / / slow speed 3

[0062] ucS_OutValue|=0x8; / / slow speed 4

[0063] / / ucS_OutValue|=0x10; / / slow speed 5

[0064] / / ucS_OutValue|=0x20; / / slow speed 6

[0065] }

[0066] if(Line2_light)

[0067] {

[0068] / / ucQ_OutValue|=0x4; / / Fast 1

[0069] ucQ_OutValue|=0x8; / / Fast 2

[0070] ucQ_OutValue|=0x2; / / Fast 3

[0071] / / ucQ_OutValue|=0x1; / / Fast 4

[0072] ucS_OutValue|=0x1; / / slow speed 1

[0073] ucS_OutValue|=0x2; / / slow speed 2

[0074] ucS_OutValue|=0x4; / / slow speed 3

[0075] ucS_OutValue|=0x8; / / slow speed 4

[0076] / / ucS_OutValue|=0x10; / / slow speed 5

[0077] / / ucS_OutValue|=0x20; / / slow speed 6

[0078] }

[0079] #endif.

[0080] In some embodiments, the protection system further includes a temperature judgment circuit, and the temperature probe is a distributed optical fiber linear temperature detector, such as Figure 9 As shown, the distributed optical fiber linear temperature detector is bundled on the outer surface of the electrical cabinet, and the temperature judgment circuit is implemented through the following steps:

[0081] S1: Preset the coordinates of the sampling points of the distributed optical fiber linear temperature detector on the electrical cabinet, collect the temperature signal T of each sampling point, and compare all the current temperature signals T with the temperature threshold T 阈 Compare and judge whether T exceeds T 阈 The number of sampling points P, when P < 3, no processing is performed, when P ≥ 3, step S2 is performed;

[0082] S2: Collect and obtain the coordinates of the corresponding P sampling points, connect any three coordinates to obtain at least one triangle, and determine whether the maximum angle of the triangle is less than 150°. If so, calculate the area S of the triangle and compare S with the area threshold S. 阈 If S<S threshold, proceed to step S3;

[0083] S3: The main control system sends a trip signal to the circuit breaker.

[0084] Among them, the area threshold S 阈 for Figure 9 The area of the circle shown, the diameter or radius of the circle can be set according to the specific situation. When the area of the triangle is smaller than the area of the circle, it proves that the temperature in the local area of the electrical cabinet has risen, that is, it may be that a certain component has risen as a whole, and there is a greater risk of arc light. At this time, tripping can timely avoid the disaster caused by arc light. When the area of the triangle is larger than the area of the circle, it proves that the temperature exceeds the temperature threshold T 阈 The three sampling points are far apart and distributed in different positions in the electrical cabinet. At this time, only a few scattered sampling points accidentally experience temperature increases, and there is no need to send a trip signal to the circuit breaker; the method of this embodiment can reduce the misjudgment rate.

[0085] In some embodiments, step S1 further includes: presetting the coordinates of sampling points of the distributed optical fiber linear temperature detector on the electrical cabinet, collecting the temperature signal T of each sampling point, comparing all current temperature signals T with the temperature threshold T 阈 Compare and judge whether T exceeds T 阈 The number of sampling points P, when 1≤P<3, proceed to step S4;

[0086] S4: Repeatedly detect the temperature T of P sampling points and determine whether the temperature T still exceeds T 阈 , if yes, proceed to step S3.

[0087] Among them, the number of repeated detections can be set according to specific circumstances, such as 2 times, 3 times. In this embodiment, when it is detected that one or two sampling points exceed the threshold, the temperature of these one or two sampling points is continuously detected. When the repeated detection result still exceeds the temperature threshold, the distributed optical fiber linear temperature detector may be detached from the preset point, causing the two sampling points to be very close. Therefore, when the temperature of these two points continues to exceed the threshold, it can be determined that the equipment in the electrical cabinet at the corresponding position is very likely to send arc light. At this time, tripping is performed to reduce the severity of the disaster.

[0088] In some embodiments, step S4 includes: repeatedly detecting the temperature T of P sampling points, and determining whether the temperature T still exceeds T 阈 If not, other parameters are tested and instructions are sent to the main control system according to the test results.

[0089] In some embodiments, detecting other parameters and sending instructions to the main control system according to the detection results includes the following steps:

[0090] S41: Determine whether arc light is detected. If yes, proceed to step S3; if not, do nothing.

[0091] S42: Determine whether the current signal exceeds the current threshold. If yes, proceed to step S3; if no, do nothing.

[0092] S43: Determine whether the voltage signal exceeds the voltage threshold. If yes, proceed to step S3; if no, do nothing.

[0093] When both sampling points have not reached the threshold, but the temperature continues to rise, first detect whether there is an arc. If so, then determine whether the current exceeds the threshold. If the current also exceeds the threshold, then determine whether the voltage exceeds the threshold. If so, trip the circuit breaker to minimize false alarms.

[0094] In some embodiments, the distance between two adjacent sampling points is between 5 cm and 20 cm.

[0095] In some embodiments, the voltage threshold is (110-120)% of the rated voltage effective value, the current threshold is (120-200)% of the effective value of the current power frequency signal and the (3-25)th odd harmonic, and the light sensitivity of the arc detection unit and the arc unit is 30,000 lux.

[0096] In certain embodiments, as Figure 10 As shown, the main control probe is connected to two current units, one arc unit and three arc detection units (probes). The arc unit is connected to three arc detection units (probes). Two circuit breakers are respectively provided on the left and right incoming lines connected to the busbar. When the current and arc exceed the threshold at the same time, a trip signal is sent to the corresponding circuit breaker.

[0097] The present invention also provides one or more arc protection systems for transformer substations for use in transformer substations of power supply bureaus and transformer substations of large mining enterprises.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An arc protection system used in a substation, characterized in that: The arc protection system includes at least two main control systems, each of which is connected to a first arc detection unit, a second arc detection unit, and a power supply module; The main control system protects at least one electrical cabinet of the substation, and the first arc detection unit and the second arc detection unit directly transmit the detected arc to the main control system; The main control system outputs a trip signal to a circuit breaker according to the received arc light, and the circuit breaker is arranged between the power supply line and the busbar of the substation; The arc protection system further includes a temperature measuring probe and a pressure measuring probe connected to the main control system. The temperature measuring probe is connected to the main control system via an arc unit. The temperature measuring probe includes an optical fiber temperature measuring probe and / or a distributed optical fiber linear temperature detector. An optical signal is transmitted between the arc unit and the temperature measuring probe via an optical fiber. An optical signal is transmitted between the arc unit and the first arc detection unit and the second arc detection unit via a temperature-sensitive optical fiber. The protection system further includes a temperature criterion circuit, wherein the temperature measuring probe is a distributed optical fiber linear temperature detector, and the distributed optical fiber linear temperature detector is bundled with the outer surface of the electrical cabinet. The temperature criterion circuit is implemented by the following steps: S1: Preset the coordinates of the sampling points of the distributed optical fiber linear temperature detector on the electrical cabinet, collect the temperature signal T of each sampling point, and compare all the current temperature signals T with the temperature threshold T 阈 Compare and judge whether T exceeds T 阈 The number of sampling points P, when 1≤P<3, proceed to step S4, when P≥3, proceed to step S2; S2: Collect and obtain the coordinates of the corresponding P sampling points, connect any three coordinates to obtain at least one triangle, and determine whether the maximum angle of the triangle is less than 150°. If so, calculate the area S of the triangle and compare S with the area threshold S. 阈 The size of 阈 When , proceed to step S3; S3: The main control system sends a trip signal to the circuit breaker; S4: Repeatedly detect the temperature T of P sampling points and determine whether the temperature T still exceeds T 阈 , if yes, proceed to step S3.

2. The arc protection system for substation according to claim 1, characterized in that: The main control system also includes a trip control circuit, which provides two output trip signals for each circuit breaker, one of which is directly connected to the circuit breaker circuit, and the other is connected to the relay of the circuit breaker trip circuit. The first arc detection unit inputs the alarm signal into the main control system and outputs the trip signal from the first path. The second arc detection unit inputs the alarm signal into the main control system and outputs the trip signal from the first path and the second path respectively.

3. The arc protection system for substation according to claim 2, characterized in that: Step S4 includes: repeatedly detecting the temperature T of P sampling points and determining whether the temperature T still exceeds T 阈 If not, other parameters are tested and instructions are sent to the main control system according to the test results.

4. The arc protection system for substation according to claim 3, characterized in that: The detecting of other parameters and sending instructions to the main control system according to the detection results includes the following steps: S41: Determine whether arc light is detected. If yes, proceed to step S3; if not, do nothing. S42: Determine whether the current signal exceeds the current threshold. If yes, proceed to step S3; if no, do nothing. S43: Determine whether the voltage signal exceeds the voltage threshold. If yes, proceed to step S3; if no, do nothing.

5. The arc protection system for substation according to claim 1, characterized in that: The distance between two adjacent sampling points is between 5cm and 20cm.

6. The arc protection system for substation according to claim 4, characterized in that: The voltage threshold is 110-120% of the rated voltage effective value, the current threshold is 120-200% of the effective value synthesized by the current power frequency signal and the 3rd to 25th odd harmonics, and the light sensitivity of the arc detection unit and the arc unit is 30,000 lux.

7. Application of the arc protection system for substations according to any one of claims 1 to 6 in power supply bureau substations and large mining enterprise substations.

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