KR20220049405A - Arc flash detection device and judgment method - Google Patents

Abstract

An arc flash detection device according to one embodiment of the present invention includes: an optical sensor module having a filter means and continuously sensing light intensity for arc detection; and a detection/analysis module having an arc checking unit which receives the sensing value of the optical sensor module to confirm an arc, and an arc analysis unit which analyzes the continuously identified arc by applying a percentage.

Description

ARC FLASH DETECTION DEVICE AND JUDGMENT METHOD

The present invention relates to an arc flash detection device to which the percent method is applied in an arc flash detection sensor, an arc flash detection device and a determination method.

The current flowing through the gas as a medium between two electrodes spaced apart or in incomplete contact with each other is called an arc. Arcs can be broadly classified into series arcs that occur in one conductor, parallel arcs that occur between two conductors, earth arcs that occur between ground and one conductor, and cross arcs that occur between other networks.

In the field of electrical safety, the detection of an electrical fault arc (flash) is the cause of an electrical fire and is an essential item to be detected for fire accidents and safety in the field of power equipment. am.

The detection technology for the prevention of electric disasters up to now measures the main line current, leakage current, voltage, arc, temperature, etc. In the case of an arc, a method of detecting and measuring an abnormal arc waveform by analyzing a current waveform at 20 kHz or higher, and a method of detecting an electrical fault arc flash of an electric device using an optical sensor are used.

In general, electrical fault arc flash occurs when the electrical device is disconnected, semi-disconnected, or in unsafe contact state. Compared to the current method, it can be detected in a non-contact type and has less noise, so it is possible to detect the size of the arc. Therefore, detection is possible only when the spark discharge lamp is directly generated in the open state.

As described above, when an electrical fault arc flash is detected by an optical method, only a spark discharge can be detected. In general, only the intensity of the flame is detected, and an alarm is generated depending on whether a spark is generated. However, even under normal circumstances, malfunctions are reduced by adjusting the sensitivity because malfunctions occur due to the operation of a circuit breaker or a momentary drop in contact by the user or strong sunlight.

In addition, since the sensitivity of the arc flash is changed according to the sensing distance, the actual use is a reality being used for fire monitoring, etc.

Therefore, even when detecting ultraviolet or infrared rays that cannot be distinguished with the naked eye, precise correction is required according to the detection distance sensitivity. Diagnosis is difficult with the current system.

Republic of Korea Registration Publication No. 10-2002606

An object of the present invention is to propose an arc flash detection apparatus and a determination method that can effectively detect arc flash as an electrical defect harmful to power equipment regardless of the distance between a measuring point and a detector.

An arc flash detection apparatus according to an aspect of the present invention includes: an optical sensor module having a filter means and continuously sensing light intensity for arc detection; And it may include a detection/analysis module having an arc checker that receives the sensing value of the optical sensor module to check the arc, and an arc analyzer that analyzes the continuously identified arc by applying a percentage.

Here, it may further include a current sensing module for sensing the current of the arc detection target site.

Here, the arc check unit, when the current value measured by the current sensing module unit does not exceed a predetermined reference current value, it is possible to stop the operation of checking the arc generation.

Here, the optical sensor module, a PMT sensor as a light receiving element; band pass filter; and an ND filter for reducing the light passing through the bandpass filter to a set level.

Here, the band-pass filter may block light having a wavelength of at least one of 340 to 300 nm, and pass light having a wavelength of any one of 240 to 200 nm.

Here, the arc analysis unit, determining whether an arc with respect to the fluctuation of the sensing value of the optical sensor module; summing the time determined as arcing as a total arc occurrence time; and calculating an arc detection rate as a ratio of the arc generation time summed from the total detection time of the photosensor module.

Here, in the step of calculating the arc detection rate, the detection rate may be calculated according to the following equation.

Arc flash determination method according to another aspect of the present invention, the method comprising the steps of: determining whether the arc with respect to the fluctuation of the sensing value of the optical sensor module; summing the time determined as arcing as a total arc occurrence time; and calculating an arc detection rate as a ratio of the arc generation time summed from the total detection time of the photosensor module.

Here, after calculating the arc detection rate, when the calculated arc detection rate exceeds a reference rate, the method may further include determining an electrical defect.

Here, in the step of calculating the arc detection rate, the detection rate may be calculated according to the following equation.

Here, the step of determining whether the arc is, determining that variations in an interval smaller than the sampling time as one variation; and determining a fluctuation longer than the minimum detection time as an arc.

Here, checking whether the measured current value is smaller than the reference current value; and if it is smaller than the reference current value, excluding from the total detection time without performing arc determination.

When the arc flash detection apparatus and/or the determination method according to the spirit of the present invention having the above configuration is implemented, it is possible to standardize and effectively detect harmful discharge/arc flash, which is an electrical defect in power equipment, regardless of the sensor, and in the field of electrical safety It has the advantage of maximally suppressing the malfunction of the high-sensitivity optical sensor used in

The arc flash detection apparatus and/or determination method of the present invention has an advantage in that it is possible to systematically manage real-time electrical equipment data in order to prevent accidents such as electric fires by complexly detecting the deterioration rate.

The arc flash detection apparatus and/or determination method of the present invention has the advantage that various arc flash sensors can be standardized and the detection/determination result is easily transmitted to a user.

The arc flash detection apparatus and/or determination method of the present invention has an advantage in that it is possible to pre-diagnose whether an electrical fault is harmful or not.

1 is a block diagram showing an embodiment of an arc flash detection apparatus according to the spirit of the present invention.
FIG. 2 is a cross-sectional view illustrating an embodiment of an optical sensor module that may be provided in the arc flash detection device of FIG. 1 .
Fig. 3 is a flow chart illustrating an arc flash determination method performed by the detection/analysis module of Fig. 1;
4 is a conceptual diagram illustrating a setting process for performing the arc flash detection method according to the flowchart of FIG. 3 and an analysis process for a detection result;

In describing the present invention, terms such as first, second, etc. may be used to describe various components, but the components may not be limited by the terms. The terms are only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

When a component is referred to as being connected or connected to another component, it may be directly connected or connected to the other component, but it can be understood that other components may exist in between. .

The terminology used herein is used only to describe specific embodiments, and is not intended to limit the present invention. The singular expression may include the plural expression unless the context clearly dictates otherwise.

In this specification, the terms include or include are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and includes one or more other features or numbers, It may be understood that the existence or addition of steps, operations, components, parts, or combinations thereof is not precluded in advance.

In addition, shapes and sizes of elements in the drawings may be exaggerated for clearer description.

The present invention is a diagnostic technology for efficient detection of arc flash for electrical safety, which enables a malfunction or the impossibility of prior recognition due to detection sensitivity, which is a problem in the prior art, and provides a conventional detection device for diagnosis using a micro arc flash. It configures security and proposes a new diagnostic method.

The technology according to the spirit of the present invention detects a harmful arc flash generated by an electrical fault in proportion to the arc flash generation time, so that it can be detected without malfunction even by using a high-sensitivity detector.

The arc flash used to detect electrical faults depends on the detection intensity, so it adjusts the appropriate sensitivity due to a malfunction. We propose a solution to the shortcomings of not being able to detect minute electrical defects that can only be detected with high sensitivity.

The general arc flash sensor that is widely used has different sensitivity characteristics for each sensor. In particular, because the detection wavelength is different, the measurement method of electrical faults is different depending on the type of sensor, and the result value according to the measurement method and distance is different, so malfunctions from the user are different. Alternatively, it is difficult to obtain reliability due to the response of the arc flash below the reference point, and data analysis is possible only through separate analysis or post-processing.

To solve this problem, the electrical fault arc flash detector detects with the maximum sensitivity and detects only the duration of the arc flash. We propose a technique for judging harmful arcs based on (%). That is, in the present invention, rather than acquiring/analyzing an image (image) using an image sensor, a method/device for determining arc through light intensity sensing using a high-sensitivity photosensor and percentage analysis of the sensed values of the photosensor is provided.

In the description of the present invention, percentage analysis means ratio analysis from the total sensing time to the detection time, and it is only natural that a representative percentage for ratio analysis is used for naming, and the scope of rights is not limited with respect to using the percentage. Do.

1 is a block diagram showing an embodiment of an arc flash detection apparatus according to the spirit of the present invention.

The illustrated arc flash detection device includes: an optical sensor module 100 having a filter means and continuously sensing light intensity for arc detection; and an arc checking unit 220 for receiving the sensing value of the optical sensor module 100 to confirm an arc, and an arc analyzing unit 240 for analyzing the continuously identified arc by applying a percentage detection/analysis It may include a module 200 .

According to implementation, a current sensing module 310 for sensing the current of the arc detection target site may be further included. In this case, when the current value measured by the current sensing module 310 does not exceed a predetermined reference current value, the arc check unit 220 may stop the check for arc generation. This is because, when the current consumption (i.e., power) of the site is less than the predetermined reference current value, the generation of noise in arc detection increases, while the risk according to the arc is low. reflects the absence of

FIG. 2 is a cross-sectional view illustrating an embodiment of an optical sensor module 100 that may be included in the arc flash detection device of FIG. 1 .

The illustrated optical sensor module 100 includes a PMT (photomultiplier tube) sensor 160 as a light receiving element; a band-pass filter 120 that passes only light in a band less than or equal to a predetermined wavelength (320 nm); and an ND (neutral density) filter 140 for reducing the light passing through the bandpass filter to a set level.

Filter means, comprising: a band pass filter (120); and a ND (neutral concentration) filter 140 , and a sensing buffer 190 for buffering the sensing value of the PMT sensor 160 is shown in the figure.

The band pass filter 120 is for blocking noise light components such as sunlight and allowing arc components to pass through, and blocks light having a wavelength greater than or equal to any one of 340 to 300 nm (more specifically, 320 nm), 240 Light having a wavelength of any one of ~ 200 nm (more specifically, 220 nm) may be implemented to pass therethrough. For example, it can be implemented as a bandpass filter having a center wavelength of a passband of 220 nm and an upper cutoff band of 320 nm. This reflects the fact that 220 nm wavelength light is known as the wavelength band of the arc generated from the copper side, and if it is set to 320 nm or less, the solar component can be greatly reduced.

Arc flashes caused by electrical faults typically span multiple wavelengths. Therefore, in the present invention, a band pass filter (BPF) 120 that passes only a specific wavelength band is fixed to the detection sensor 160 to detect only a specific band. At this time, the pass wavelength of the filter 120 is configured to be variable according to the material of the detection target for detecting harmful discharge or arc flash. The harmful discharge or arc flash that has passed through the BPF 120 can be directly detected using an optical sensor, but at this time, the detector can react by solar radiation such as sunlight. It is advantageous to design the filter so that detection is possible only in the ultraviolet region, which is insensitive to light. In this case, a sensitivity offset function may be added by using the ND filter 140 to distinguish it from general ultraviolet rays of sunlight.

The illustrated optical sensor uses an optical sensor that detects the maximum sensitivity in the current arc discharge or arc flash, and the PMT 160 is applied as the optical sensor because the sensitivity of the PMT is very high.

The PMT sensor 160 does not form a two-dimensional image and senses only the light intensity, but acquires continuous sensing values and stores them in the sensing buffer 190 .

The PMT sensor 160 is a PMT (photomultiplier tube) type optical sensor, which detects visible light and uses the emission of secondary electrons through a vacuum tube to amplify the electron current of minute photoelectrons without noise, so the sensitivity (amplification factor) ) has very high properties.

The ND filter 140 is the PMT sensor 160 with high sensitivity when the amount of input light itself is significantly different depending on the installation location of the optical sensor module 100 or the long interval time range (eg, night/day). ) to prevent photosaturation. Therefore, it is advantageous to be able to adjust the transmittance of the ND filter 140 by the control unit for controlling the light sensing operation.

The arc flash detection apparatus shown in FIG. 1 can detect arc flash with the following algorithm.

Briefly, first, the arc length and arc generation interval of the detected harmful discharge or electrical fault arc flash are measured. At this time, if the arc length and arc interval are shorter than the sampling of the sensor for arc flash detection, it is treated as one arc. The reason for this is that it is an algorithm that can reduce malfunctions according to the detection cycle of the optical sensor and enables more precise detection. The algorithm may be performed by the detection/analysis module 200 of FIG. 1 .

3 is a flowchart illustrating an arc flash determination method performed by the detection/analysis module 200 (more specifically, the arc confirmation unit 220) of FIG. 1 .

The arc flash determination method shown includes the steps of determining whether an arc is in the received (S11) sensing value fluctuation of the optical sensor module (S12 ~ S17); summing the time determined as an arc as a total arc generation time (S18); and calculating an arc detection rate as a ratio of the arc generation time summed from the total detection time of the photosensor module.

Specifically, the step of determining whether the arc (S12 to S17) includes the steps of determining whether fluctuations (arc candidates) with an interval smaller than a predetermined sampling time (arc candidates) are one fluctuation (S12 to S15); and determining a fluctuation longer than a predetermined minimum detection time as an arc (S16, S17).

Although not shown, when the current sensing module 310 of FIG. 1 is provided, checking whether the measured current value is smaller than a predetermined reference current value; and if it is smaller than the reference current value, excluding from the total detection time without performing arc determination.

If the sensed value detected at each point in time (S11) is greater than a predetermined reference value, it is regarded as a sensing value change to be determined, and the length (a) and interval (b) of the sensing value change, which is an arc candidate signal, is measured (S12).

In FIG. 3, as an arc generation time detection algorithm according to the minimum reference value, 100us is applied to the sampling time for the sensor (or the resolution of the sensor), and an example of determining an arc when the duration is 5000us or more is concretely illustrated.

4 is a conceptual diagram illustrating a setting process for performing the arc flash detection method according to the flowchart of FIG. 3 and an analysis process for a detection result.

As shown, by the main program of the detection/analysis module 200, it is possible to set the reference value or the minimum detection time for arc generation (S61, S62), and set the sensing value from the optical sensor module 100 In accordance with the synchronization (S63), the arc determination according to the set standard is performed (S64). Information on the determined arc may be output as a graph (S66) or output as a result table (S67).

In the flowchart of FIG. 3 , a reference point having a weak arc generation time may be determined.

In the case of measuring the current with the current sensing module 310 of FIG. 1, even if the measured current is less than 30% of the rated current or less than a certain reference point, since it is determined that the arc is generated according to no load, the sensing value in this section is the arc It can be excluded from flash detection.

The arc density, which can be said to be the size of arc generation in the detection of a harmful discharge or arc flash caused by an electrical fault, may be irregular. Therefore, the transmittance of the ND filter can be adjusted to enable detection by determining only the density above a certain standard as the starting point and the ending point, or a threshold reference point can be applied in software.

Steps S71 to S75 of FIG. 4 show the analysis process performed by the arc analysis unit 220 in the form of a main program.

As shown, by using the raw data (S72) and the analysis data (S73), it is determined whether there is a risk (abnormality) to the target site (S27), and the result of the determination is provided to the administrator as an Excel report (S75), etc. can As shown in the figure, the Excel report may include the number of arc flash occurrences, arc size reference (change) analysis, percentage (ratio) reference time change, percentage, distance from the detector point, maximum density analysis, and the like.

The arc analyzer 220 calculates and uses the arc flash detection rate in the analysis, and the arc flash detection rate may be finally detected by Equation 1 below. In other words, in a manner in which the degree of deterioration of power equipment is expressed as an arc flash detection rate, a deterioration rate determination technique using the % method can be presented.

In the above formula, the sum of arcs of molecules is the detection time when the rated current greater than the reference value flows, and the arc generation time less than the reference point is excluded, and the verification algorithm for continuous arcs is applied. It may be the sum of the arcs.

In the above formula, the total operating time of the denominator is the total operating time of the arc when a value greater than or equal to the reference current flows. You can set it so that no value is displayed.

In the analysis process, after calculating the arc detection rate according to Equation 1, if the calculated arc detection rate exceeds the reference rate, it can be seen that determining an electrical defect is performed.

By using the detection rate according to the above equation, the duration of the arc flash, not the power density of the arc flash, is detected, so that the sensitivity characteristic according to the distance between the electric fault arc flash occurrence point and the detector can be solved. , as it is based on percentage (%), it is possible to fundamentally solve malfunctions for arc flashes less than the reference value.

For example, even when the arc flash generation point and the detector are far apart, the arc flash detection device according to the present invention increases the sensitivity to increase the average signal for detection, even without separately adjusting the distance. Accordingly, the adjustment according to the remote environmental condition is also performed.

In particular, the present technology has the advantage that it is possible to determine whether the electrical fault is harmful because it is possible to detect the arc flash repeatedly generated by the electrical fault with a detection rate (%). For example, the arc flash detection rate (%) according to the above equation is set in two stages, and at a higher detection rate, it is immediately determined as an electrical fault, and at a lower detection rate, the need for prior diagnosis is notified. can

The arc flash detection apparatus according to the spirit of the present invention as described above uses the % method to effectively detect harmful electrical defects that occur due to breakage, contact amount, etc. regardless of the distance between the measurement point and the detector. In order to prevent accidents such as electric fires by complex detection, it is possible to support the systematic management of real-time electrical equipment data.

The degradation rate determination technology using the percentage method, which is the core content of this patent, is a technology that can standardize various arc flash sensors and its algorithm has high compatibility using the concept of percentage and can be easily delivered to users such as system managers. there is.

In particular, electrical faults such as hazardous discharge/arc flash/leakage current are essential items to be detected for safety in the field of power facilities to which DC distributed power is applied. In bar, the arc flash detection apparatus according to the spirit of the present invention was able to obtain a test result that dramatically improved the faster response speed, precision, and sensitivity by 10 times or more compared to the existing ones.

Those skilled in the art to which the present invention pertains should understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential characteristics thereof, so the embodiments described above are illustrative in all respects and not restrictive. only do The scope of the present invention is indicated by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. .

100: optical sensor module
220: arc confirmation unit
240: arc analysis unit
200: detection/analysis module
310: current sensing module
160: PMT (photomultiplier tube) sensor
120: band pass filter
140: ND (neutral density) filter
190: sensing buffer

Claims (12)

an optical sensor module having a filter means and continuously sensing light intensity for arc detection; and
A detection/analysis module having an arc confirmation unit that receives the sensing value of the optical sensor module to check an arc, and an arc analyzer that analyzes the continuously identified arc by applying a percentage
Arc flash detection device comprising a.
According to claim 1,
Current sensing module to sense the current of the arc detection target site
Arc flash detection device further comprising a.
3. The method of claim 2,
The arc check unit, if the current value measured by the current sensing module unit does not exceed a predetermined reference current value, the arc flash detection device to stop the operation of checking the arc generation.
The method of claim 1,
The optical sensor module,
a PMT sensor as a light receiving element;
band pass filter; and
ND filter that reduces the light passing through the bandpass filter to a set level
Arc flash detection device comprising a.
5. The method of claim 4,
The bandpass filter is
An arc flash detection device that blocks light having a wavelength greater than or equal to any one of 340 to 300 nm and allows light having a wavelength of any one of 240 to 200 nm to pass therethrough.
The method of claim 1,
The arc analysis unit,
determining whether an arc is detected with respect to a change in a sensing value of the optical sensor module;
summing the time determined as arcing as a total arc occurrence time; and
Calculating an arc detection rate as a ratio of the arc generation time summed from the total detection time of the optical sensor module
An arc flash detection apparatus for performing an arc flash determination method comprising a.
7. The method of claim 6,
In the step of calculating the arc detection rate,
An arc flash detection device for calculating a detection rate according to the following equation.

determining whether an arc is detected with respect to a change in a sensing value of the optical sensor module;
summing the time determined as arcing as a total arc occurrence time; and
Calculating an arc detection rate as a ratio of the arc generation time summed from the total detection time of the optical sensor module
Arc flash determination method comprising a.
9. The method of claim 8,
After calculating the arc detection rate,
Determining an electrical defect when the calculated arc detection rate exceeds a reference rate
Arc flash determination method further comprising.
9. The method of claim 8,
In the step of calculating the arc detection rate,
An arc flash determination method for calculating a detection rate according to the following equation.

9. The method of claim 8,
The step of determining whether the arc is,
determining fluctuations at intervals smaller than the sampling time as one fluctuation; and
Determining a fluctuation longer than the minimum detection time as an arc
Arc flash determination method comprising a.
9. The method of claim 8,
checking whether the measured current value is smaller than a reference current value; and
If it is less than the reference current value, the arc determination is not performed and the step of excluding from the total detection time
Arc flash determination method further comprising.

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