Power system protection device capable of detecting circuit abnormality and control method thereof

Abstract

The present invention relates to a power system protection device capable of detecting whether an abnormality occurs in a circuit of a voltage or current system including a sensing unit for a voltage or current signal. The power system protection device comprises: a measurement unit for measuring a current or voltage of the system; a detection channel for amplifying a measurement result of the measurement unit using a preset default gain and an amplification gain corresponding to a multiple of the default gain, and detecting, at a preset sampling rate, a default-gain sample obtained by sampling the result amplified using the default gain and an amplified-gain sample obtained by sampling the result amplified using the amplification gain; and a detection unit for calculating a ratio of a sample value of the amplified-gain sample to a sample value of the default-gain sample, comparing a magnitude of the calculated ratio with a magnitude of the pre-stored amplification gain, and determining whether an abnormality occurs in a circuit unit according to a result of the comparison.

Description

Power system protection device capable of detecting circuit abnormalities and control method thereof

[0001] The present invention relates to a protection device for a power system capable of detecting whether a circuit abnormality of a voltage or current system including a sensing unit for a voltage or current signal is present, and a control method for the protection device.

[0002] Protection devices used in power systems measure current or voltage from the system and determine whether current or voltage abnormalities exist based on the measured results. To achieve this, protection devices typically measure the system's current or voltage as an analog value, amplify this measured analog value through an analog circuit, such as an amplifier circuit, and then convert the amplified analog value into a digital value.

[0003] However, when an accident or external disturbance occurs in the system, a fault current or strong noise may occur. In this case, the analog circuit of the protection device may be damaged due to the fault current or noise. In particular, the analog circuit includes a plurality of IC semiconductors, and damage to the IC semiconductor elements may cause misamplification of the system current or voltage. Therefore, even when the actual system voltage or system current value is low or normal, an excessive value may be transmitted to the ADC (Analog Digital Converter) due to misamplification, or conversely, when an overcurrent or overvoltage occurs due to a system fault, a value within the normal range may be transmitted to the ADC due to misamplification. Then, the control unit of the protection device may misrecognize the system current or system voltage, which may cause the circuit breaker to perform a trip operation even when the system current or voltage is normal, or may prevent the circuit breaker from performing a trip even when an accident occurs.

[0004] Accordingly, in order to increase the reliability of the protection device, a method for detecting abnormalities in the analog circuit that transmits analog measurement values ​​to the ADC of the protection device is currently being studied.

[0005] The present invention aims to solve the above-mentioned problem and other problems, and provides a protection device for a power system capable of detecting an abnormality in an analog circuit part that transmits the analog measurement value to an ADC before detecting the state of the current or voltage of the system, and a control method of the protection device.

[0006] According to one aspect of the present invention to achieve the above or other purposes, a power system protection device according to an embodiment of the present invention is characterized by including a measuring unit that measures current or voltage of a system, a detection channel that amplifies a measurement result of the measuring unit with a preset basic magnification and an amplification magnification according to a multiple of the basic magnification, detects a basic sample sampled from a result amplified with the basic magnification according to a preset sampling rate, and an amplification sample sampled from a result amplified with the amplification magnification, and a detection unit that calculates a magnification of a sample value of the amplified sample with respect to a sample value of the basic sample, compares the calculated magnification with the magnitude of the amplification magnification stored in advance, and determines whether a circuit unit is abnormal based on the comparison result.

[0007] In one embodiment, the detection channel is characterized by including a basic channel including a basic amplifier unit that amplifies the measurement result of the measurement unit at the basic magnification, and a basic sampling unit that samples the basic sample from the measurement result amplified at the basic magnification according to the preset sampling rate, and an amplification channel including a channel amplifier unit that amplifies the measurement result of the measurement unit at the amplification magnification, and a channel sampling unit that samples the amplified sample from the measurement result amplified at the amplification magnification according to the preset sampling rate.

[0008] In one embodiment, the power system protection device has a plurality of detection channels, and the plurality of detection channels are characterized in that the sampling rates for sampling the basic sample and the amplified sample are different from each other.

[0009] In one embodiment, the minimum speed among the different sampling speeds is characterized in that it is faster than the speed at which the power system protection device samples samples to determine whether the system is abnormal based on the current or voltage of the system.

[0010] In one embodiment, the sampling rates of each of the plurality of detection channels are characterized in that they are in a small relationship with each other.

[0011] In one embodiment, the detection unit is characterized in that it converts the sample value of the basic sample and the sample value of the amplified sample into digital values ​​through an ADC (Analog Digital Converter), and calculates a ratio of the sample value of the amplified sample to the sample value of the basic sample converted into a digital value.

[0012] In one embodiment, each of the plurality of detection channels corresponds to a different phase of the system, and the detection unit compares the magnifications of the sample value of the amplified sample with the sample value of the basic sample detected in the detection channels corresponding to each phase with the sizes of the amplification magnifications stored in advance corresponding to each detection channel to detect whether there is an abnormality in at least one circuit component related to each phase of the system.

[0013] In one embodiment, the different phases of the system include an A phase, a B phase, a C phase, an N phase, and a ZCT (Zero Current Transformer) phase, and at least one detection channel having a different sampling rate is assigned to each of the A phase, B phase, C phase, N phase, and ZCT phase.

[0014] In one embodiment, the basic sampling unit and the channel sampling unit are variable sampling units capable of changing a sampling rate, and the detection unit is characterized in that it changes the preset sampling rate set in the basic sampling unit and the channel sampling unit according to preset conditions.

[0015] In one embodiment, the detection unit is characterized in that, when the result of comparing the calculated magnification with the size of the previously stored amplification magnification shows that no abnormality in the circuit unit is detected more than a preset number of times, the detection unit changes the preset sampling rate.

[0016] In one embodiment, the detection unit changes the preset sampling rate within a range of a maximum sampling rate and a minimum sampling rate, wherein the minimum sampling rate is a sampling rate that is faster than a rate at which the power system protection device samples samples to determine whether the power system is abnormal based on the current or voltage of the power system, and the maximum sampling rate is a maximum sampling rate that is faster than the minimum sampling rate and is determined according to the hardware performance of the power system protection device.

[0017] According to one aspect of the present invention to achieve the above or other purposes, a control method of a power system protection device according to an embodiment of the present invention is characterized by including the steps of measuring current or voltage of a system, a step of amplifying the measurement result with a preset basic magnification and an amplification magnification according to a multiple of the basic magnification, a step of detecting a basic sample sampled from a result amplified with the basic magnification and an amplification sample sampled from a result amplified with the amplification magnification according to a preset sampling rate, a step of digitizing a sample value of the basic sample and a sample value of the amplification sample, a step of calculating a magnification of the sample value of the digitized basic sample and the sample value of the amplification sample, and a step of determining whether a circuit part related to the amplification is abnormal based on whether a difference between the calculated magnification and the size of the amplification magnification stored in advance is within a preset error range.

[0018] In one embodiment, the step of detecting the amplified sample is characterized in that the step of detecting a plurality of pairs of the basic sample and the amplified sample sampled at different sampling rates is a step of detecting a plurality of pairs of the basic sample and the amplified sample sampled at different sampling rates through a plurality of detection channels that detect the basic sample and the amplified sample at different sampling rates, respectively.

[0019] In one embodiment, the step of determining whether the circuit unit is abnormal is characterized in that the step of determining whether the circuit unit is abnormal is a step of comparing the ratio of the basic sample value and the amplified sample value calculated for each pair of the basic sample and the amplified sample with the size of the amplification ratio assigned to each detection channel to determine whether the circuit unit is abnormal for each different sampling speed.

[0020] In one embodiment, the different sampling rates are characterized in that they are inversely related to each other.

[0021] In one embodiment, the minimum speed among the different sampling rates is characterized in that it is a sampling rate that is faster than the speed at which the power system protection device samples samples to determine whether the system is abnormal based on the current or voltage of the system.

[0022] In one embodiment, the step of determining whether the circuit unit is abnormal is characterized by changing the preset sampling rate when the accumulated number of times the circuit unit is not determined to be abnormal reaches a preset number.

[0023] The effects of the power system protection device and the control method of the protection device according to the present invention are described as follows.

[0024] According to at least one of the embodiments of the present invention, the power system protection device has a plurality of channels for amplifying analog measurement values ​​by different multiples and sampling values ​​from the amplified measurement values, and compares the amplified results from each channel with each other to calculate an amplification factor for each channel and compares the calculated amplification factor with a pre-stored amplification factor, thereby detecting whether there is a circuit abnormality in an analog circuit section. In addition, when there is no circuit abnormality in the analog circuit section, there is an effect that the reliability of the protection device can be improved by determining whether there is an abnormality in the current or voltage of the system based on a digital measurement value converted from the analog measurement value.

[0025] In addition, the present invention has a plurality of detection channels having different sampling rates, and detects whether there is an abnormality in an analog circuit based on the amplification ratio of each detection channel, thereby enabling the detection of an abnormality in an analog circuit more quickly.

[0026] In addition, the present invention samples analog measurement values ​​at a sampling rate that is at least a preset level faster than the sampling rate of analog measurement values ​​for determining whether the current or voltage of the system is abnormal, thereby enabling the detection of an abnormality in the analog circuit of the protection device before the detection of an abnormality in the current or voltage of the system. Accordingly, there is an effect that the detection of an abnormality in the current or voltage of the system can be performed only when there is no abnormality in the analog circuit.

[0027] In addition, the present invention has the effect of determining an optimal sampling rate by dynamically adjusting a sampling rate for sampling an amplified measurement value based on a history of detecting an abnormality in an analog circuit, thereby enabling the determination of an abnormality in an analog circuit before the determination of an abnormality in the current or voltage of the system, as well as minimizing the computational load and driving load of a protection device.

[0028] Figure 1 is a block diagram showing the basic configuration of a protection device that determines whether the current or voltage of a system is abnormal.

[0029] FIG. 2A is a conceptual diagram illustrating a protection device having a detection channel including a basic channel and an amplification channel according to an embodiment of the present invention.

[0030] FIG. 2b is a block diagram illustrating a configuration of a protection device having detection channels each having a different sampling rate according to an embodiment of the present invention.

[0031] FIG. 3 is a flowchart illustrating an operation process for determining whether an analog circuit part is abnormal by a protection device according to an embodiment of the present invention.

[0032] Figure 4a is an example diagram showing examples of sampling points at which sampling is performed at different sampling rates.

[0033] FIG. 4b is an exemplary diagram showing an example in which an error value is detected due to an abnormality in an analog circuit based on samples sampled at different sampling rates.

[0034] FIG. 5 is a flowchart illustrating an operation process for determining whether there is an abnormality in the analog circuit for each phase of the system when a protection device according to an embodiment of the present invention is configured as in FIG. 2b.

[0035] FIG. 6 is a block diagram illustrating the configuration of a protection device according to an embodiment of the present invention in which the sampling rate and amplification ratio of the basic channel and the amplification channel are formed to be variable.

[0036] FIG. 7 is a flowchart illustrating an operation process for changing a sampling rate and determining whether an analog circuit part is abnormal in a protection device according to an embodiment of the present invention.

[0037] It should be noted that the technical terms used herein are used merely to describe specific embodiments and are not intended to limit the present invention. Furthermore, singular expressions used herein include plural expressions unless the context clearly dictates otherwise. The suffixes "module" and "part" used in the following description for components are assigned or used interchangeably solely for the convenience of writing the specification, and do not in themselves have distinct meanings or roles.

[0038] In this specification, the terms “comprises” or “includes” should not be construed to necessarily include all of the components or steps described in the specification, and some of the components or steps may not be included, or additional components or steps may be included.

[0039] In addition, when describing the technology disclosed in this specification, if it is determined that a detailed description of a related known technology may obscure the gist of the technology disclosed in this specification, the detailed description is omitted.

[0040] In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention. In addition, not only each embodiment described below, but also a combination of embodiments may correspond to the spirit and technical scope of the present invention as modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

[0041] Figure 1 is a block diagram showing the basic configuration of a protection device that determines whether the current or voltage of a system is abnormal.

[0042] Referring to FIG. 1, a protection device according to an embodiment of the present invention may include a measuring unit (20) that measures current or voltage of a system (10), an amplifier unit (30) that amplifies an analog measurement value measured by the measuring unit (20), a sampling unit (40) that samples the measurement value (analog) amplified by the amplifier unit (30), and an ADC (50) that converts the sampled value sampled by the sampling unit (40) into a digital value. In addition, the protection device may be configured to include a detection unit (60) that determines whether the current or voltage of the system is abnormal based on the measurement value of current or voltage converted into a digital value by the ADC (50).

[0043] Here, the components illustrated in the above drawing 1 are not essential for implementing a protection device according to an embodiment of the present invention, and thus, the protection device described in this specification may have more or fewer components than the components listed above.

[0044] Meanwhile, the protection device according to an embodiment of the present invention can determine whether there is an abnormality in components including IC semiconductors that constitute an analog circuit unit that transmits an analog measurement value measured in a measurement unit (20) to an ADC (50), that is, a circuit unit including an amplifier unit (30) and a sampling unit (40).

[0045] To this end, the protection device according to an embodiment of the present invention can amplify the same analog measurement value measured by the measurement unit (20) at different magnifications, and perform sampling from each of the analog measurement values ​​amplified at the different magnifications. In addition, the device can calculate an amplification magnification between different sample values ​​obtained through the sampling, and compare the calculated amplification magnification with a preset amplification magnification to detect whether there is an abnormality in the analog circuit.

[0046] FIG. 2A is a conceptual diagram illustrating a protection device having a detection channel including a basic channel and an amplification channel according to an embodiment of the present invention.

[0047] Referring to FIG. 2a, a protection device according to an embodiment of the present invention may include a channel (hereinafter, basic channel) (210) having a basic amplifier (211) that amplifies an analog measurement value measured by a measurement unit (202) at a preset basic magnification and a basic sampling unit (212) that performs sampling according to a preset sampling rate (basic sampling rate) for the analog measurement value amplified by the basic amplifier (211).

[0048] In this case, the basic magnification may be a magnification at which the detection unit (206) amplifies the analog measurement value measured by the measurement unit (202) to determine whether there is an abnormality in the current or voltage of the system. In addition, the basic sampling rate may be a sampling rate at which the detection unit (206) obtains a sample value from the amplified analog measurement value to determine whether there is an abnormality in the current or voltage of the system.

[0049] That is, the magnification (basic magnification) and sampling speed (basic sampling speed) of the basic channel (210) are the amplification magnification and sampling speed for the detection unit (206) to determine whether there is an abnormality in the current or voltage of the system, and when there is no abnormality in the analog circuit unit, the detection unit (206) can determine whether there is an abnormality in the current or voltage of the system based on the sample value obtained from the basic channel (210).

[0050] Meanwhile, a protection device according to an embodiment of the present invention may include a channel (hereinafter referred to as an amplification channel) (220) having a channel amplification unit (221) that amplifies an analog measurement value measured by a measurement unit (202) at an amplification rate greater than the basic rate, and a channel sampling unit (222) that performs sampling according to a preset sampling rate (e.g., basic sampling rate) for the analog measurement value amplified by the channel amplification unit (221).

[0051] In this case, the amplification magnification of the channel amplifier (221) may be an integer multiple of the basic magnification. For example, if the basic magnification is 1 (in this case, the basic channel (210) may be a non-amplified channel), the amplification magnification of the channel amplifier (221) may be set to an integer greater than 1 (e.g., 2x, 3x, ...). In addition, if the basic magnification is 10x, the amplification magnification of the channel amplifier (221) may be set to a multiple of 10x, which is an integer multiple of the basic magnification (e.g., 20x, 30x, ...). Accordingly, the magnification of the channel amplifier (221) may amplify the analog measurement value by an integer multiple of the amplification magnification of the basic amplifier (211).

[0052] Meanwhile, as shown in Fig. 2a, one basic channel can be paired with one amplification channel to form one detection channel (200). Accordingly, the sampling rates of the basic channel (210) and the amplification channel (220) forming the detection channel (200) of Fig. 2a can be the same. That is, the sampling rate of the basic sampling unit (212) and the sampling rate of the channel sampling unit (222) can be the same.

[0053] Meanwhile, the ADC (204) can receive a first sample sampled from the sampling unit (basic sampling unit (212)) of the basic channel (210) and convert it into a digital value (first digital measurement value). In addition, the ADC (204) can receive a second sample sampled from the sampling unit (channel sampling unit (222)) of the amplification channel (220) and convert it into a digital value (second digital measurement value). Then, each converted digital measurement value can be input to the detection unit (206).

[0054] Then, the detection unit (206) can calculate the ratio of the first digital measurement value and the second digital measurement value. In this case, if the analog circuit is normal, the ratio between the first digital measurement value and the second digital measurement value may be the same as the ratio of the amplification magnification of the basic amplifier unit (211) and the amplification magnification of the channel amplifier unit (221). In this case, as described above, since the amplification magnification of the channel amplifier unit (221) is an integer multiple of the amplification magnification of the basic amplifier unit (211), the ratio of the first digital measurement value and the second digital measurement value can be calculated as an integer.

[0055] Then, the detection unit (206) can compare the ratio of the first digital measurement value and the second digital measurement value produced with the amplification multiple of the amplification factor of the channel amplification unit (221) for the basic magnification stored in the memory (207).

[0056] And if the difference between the ratio of the first digital measurement value and the second digital measurement value and the amplification multiple previously stored in the memory (207) as a result of the comparison is within the preset error range, the detection unit (206) can determine that there is no abnormality in the analog circuit of the protection device. Then, the detection unit (206) can amplify the analog measurement value measured by the measurement unit (202) and detect the magnitude of the current or voltage of the system based on the sample value sampled from the amplified analog measurement value. And, whether there is an abnormality can be determined based on the magnitude of the current or voltage of the system detected.

[0057] Here, the detection unit (206) can use the sample value acquired from the basic channel (210) as a sample value for detecting the magnitude of the current or voltage of the system. That is, the protection device according to an embodiment of the present invention can detect the magnitude of the current or voltage of the system by using the sample value that was used to detect whether the analog circuit unit is abnormal without the need to acquire a separate sample, if the analog circuit unit is normal. Therefore, a time delay for detecting whether the analog circuit unit is abnormal may not occur.

[0058] On the other hand, if the difference between the ratio of the first digital measurement value and the second digital measurement value and the amplification multiple previously stored in the memory (207) as a result of the above comparison is outside the preset error range, the detection unit (206) can determine that there is an abnormality in the analog circuit of the protection device. Then, the detection unit (206) can transmit abnormality information indicating the abnormality in the determined analog circuit to a preset server or terminal. Here, the terminal may include a PC or laptop, a PDA, a mobile terminal such as a smartphone, etc. that is preset to receive the abnormality information.

[0059] And, depending on the control signal received from the server or terminal, or automatically upon determining an abnormality in the analog circuit, the detection unit (206) can perform a trip operation by controlling a blocking unit (not shown) to block the connection between the load and the system.

[0060] However, in the case where the sample value for detecting the magnitude of the current or voltage of the system is directly used to determine whether there is an abnormality in the analog circuit as described above, the determination of whether there is an abnormality in the system according to the magnitude of the current or voltage of the system can be made simultaneously with the determination of whether there is an abnormality in the analog circuit.

[0061] That is, in the case of the protection device according to the embodiment of the present invention illustrated in Fig. 2a, not only can the determination of whether the system is in an abnormal state be performed, but also the determination of whether the analog circuit part is in an abnormal state can be performed. In this case, if the detection unit (206) determines that there is an abnormality in the analog circuit part as a result of the determination of whether there is an abnormality, it can ignore the result of the determination of the system's abnormal state, notify the server or terminal of the result of the determination of the analog circuit part as an abnormality, and perform a trip operation.

[0062] Meanwhile, if there is a problem with the analog circuit, the current or voltage of the system is likely to be misjudged. Therefore, as described above, if there is a problem with the analog circuit, the results of the system abnormality determination may be ignored. Therefore, it may be more desirable to determine whether there is a problem with the analog circuit before determining the system abnormality.

[0063] However, as illustrated in Fig. 2a, if the sampling of samples for detecting an abnormality in the analog circuit is performed at the same speed as the sampling speed of the samples for calculating the magnitude of the current or voltage of the system, the abnormal state of the system can be determined based on the magnitude of the current or voltage of the system at the same time as the determination of an abnormality in the analog circuit. Accordingly, it goes without saying that the sampling speed of the samples for determining an abnormality in the analog circuit can be made faster than the sampling speed of the samples for determining the state of the system so that the abnormality in the analog circuit can be determined before the point in time at which the state of the system is determined by the current or voltage of the system.

[0064] To this end, the present invention may further include at least one detection channel for determining whether there is an abnormality in an analog circuit at a sampling rate faster than a sampling rate for obtaining samples for determining the status of the system.

[0065] FIG. 2b is a block diagram illustrating a configuration of a protection device according to an embodiment of the present invention, which includes a plurality of detection channels that perform sampling at a rate faster than a sampling rate for obtaining samples for calculating the magnitude of the current or voltage of the system.

[0066] Referring to FIG. 2b, a protection device according to an embodiment of the present invention may have a plurality of detection channels, each of which is composed of a pair of a basic channel and an amplification channel.

[0067] In this case, as shown in Fig. 2b, the protection device may have n detection channels ranging from a first detection channel (310), a second detection channel (320) to an n-th detection channel. Here, the first basic channel (311) may be paired with a first amplification channel (312) to form the first detection channel (310), and the second basic channel (321) may be paired with a second amplification channel (322) to form the second detection channel (320). Similarly, the n-th basic channel may be paired with an n-th amplification channel to form the n-th detection channel.

[0068] Meanwhile, the sampling rates of each detection channel may be different. The sampling rates may include both the sampling rates of the basic channel and the sampling rates of the amplification channels. That is, the sampling rates of the basic channel and the amplification channel included in one detection channel are the same, and the sampling rates of the basic sampling section and the channel sampling section of each detection channel may be different for each detection channel.

[0069] For example, the sampling rate of the first basic sampling unit and the sampling rate of the first channel sampling unit may be the same (sampling rate of the first detection channel). However, the sampling rate of the second basic sampling unit and the sampling rate of the second channel sampling unit (sampling rate of the second detection channel) may each be different from the sampling rate of the first detection channel. In other words, the basic channel and the amplification channel constituting one detection channel may be channels that sample measurement values ​​amplified at different magnifications at the same sampling rate.

[0070] In this case, if the sampling speed of the first detection channel (310) is the speed at which samples are sampled to calculate the size of the current or voltage of the system, the sampling speed of the second detection channel (320) may be a speed faster than the sampling speed of the first detection channel.

[0071] In this way, since the sampling speed of the second detection channel (320) is faster, the number of samples acquired from the second detection channel (320) within the same time period may be greater than that of the first detection channel (310). That is, since a greater number of samples are acquired from the second detection channel (320) during the time it takes for one sample to be sampled from the first detection channel (310), in the event of an abnormality in the analog circuit, an abnormal value may be detected first from the sample acquired from the second detection channel (320) before the abnormal value is detected from the sample acquired from the first detection channel (310).

[0072] In this case, if the detection unit (303) determines whether there is an abnormality in the current and voltage of the system based on the sample obtained from the basic channel (the first basic channel (311)) of the first detection channel (310), that is, if the sampling speed of the first basic sampling unit is the same as the sampling speed of the sample for determining whether there is an abnormality in the system, before the detection unit (303) determines whether there is an abnormality in the current and voltage of the system, whether there is an abnormality in the analog circuit can first be determined from the abnormal value detected from the second detection channel (320).

[0073] Meanwhile, since the faster the abnormality of an analog circuit can be determined, the better, the faster the sampling speed of the remaining detection channels excluding the first detection channel (310) (assuming that the abnormality of the system is determined based on the sample obtained from the basic channel (first basic channel (311)) of the first detection channel (310)) may be advantageous. However, the faster the sampling speed, the more the computational load of the detection unit (303) may be increased, and the faster the sampling speed, the more expensive the sampling unit is required. Therefore, the sampling speed of at least one remaining detection channel may be determined in consideration of the hardware performance and cost of the detection unit (303). In this case, at least one of the plurality of detection channels formed in advance may be selected to be activated in consideration of the hardware performance and cost of the detection unit (303).

[0074] Meanwhile, if an error occurs in an analog circuit, the error caused by the error may occur for a certain period of time and then be restored to its original state, repeating non-periodically. In this case, if sampling is performed during the time when the error occurs, the presence of an error in the analog circuit can be detected based on the sample value. However, if this is not the case, that is, if the error occurs and is then restored again during the sampling cycle, the presence of an error in the analog circuit may not be detected.

[0075] In this case, by using detection channels with different sampling rates, the sample interval for detecting errors occurring in the analog circuit can be further refined. For example, when detecting an abnormality in the analog circuit by further using a third detection channel with a different sampling rate from the second detection channel (320), even when an error that cannot be detected at the sampling rate of the second detection channel (320) occurs (e.g., when an error occurs between samples according to the sampling rate of the second detection channel (320), the error can be detected through samples sampled according to the sampling rate of the third detection channel.

[0076] To this end, when detecting anomalies in an analog circuit using multiple detection channels with different sampling rates, the sampling rates of at least some of the multiple detection channels may be relatively prime to each other. In this case, if the sampling rates are relatively prime to each other, the points in time at which samples are detected do not overlap, and thus the time intervals over which sampling is performed can be further segmented according to the sampling rate. Therefore, anomalies in an analog circuit can be detected more accurately and quickly.

[0077] Additionally, the multiple of the amplification factor of the channel amplifier with respect to the amplification factor of the basic amplifier (basic magnification) in each detection channel may be different for each detection channel.

[0078] For example, the amplification factor of the first channel amplifier of the first detection channel (310) may be twice the amplification factor (basic factor) of the first basic amplifier of the first detection channel (310). On the other hand, the amplification factor of the second channel amplifier of the second detection channel (320) may be three times the amplification factor (basic factor) of the second basic amplifier of the second detection channel (320). In addition, the amplification factor of the third channel amplifier of the third detection channel may be five times the amplification factor (basic factor) of the third basic amplifier of the third detection channel.

[0079] That is, each detection channel may be a channel in which at least one of the sampling rate (sampling rate of the basic sampling unit and sampling rate of the channel sampling unit) and the multiplier of the channel amplification unit with respect to the basic magnification (amplification magnification of the basic amplification unit) is different.

[0080] Meanwhile, when multiple detection channels are provided in this manner, the ADC (302) of the protection device according to an embodiment of the present invention can convert sample values ​​received from the basic channel and amplification channel of each detection channel into digital values. Then, the sample values ​​converted into digital values ​​can be input to the detection unit (303).

[0081] Then, the detection unit (303) can receive the digitized sample value (first sample value) of the basic channel and the digitized sample value (second sample value) of the amplification channel received from each detection channel. Then, the ratio of the first sample value and the second sample value can be calculated for each detection channel. Then, the calculated ratio value for each detection channel can be compared with the amplification factor value for each detection channel previously stored in the memory (305).

[0082] Here, the amplification factor value for each detection channel may be a multiple of the amplification factor of the channel amplifier for the basic factor for each detection channel. Therefore, if there is no abnormality in the analog circuit, the ratio of the first sample value and the second sample value produced in each detection channel (the ratio of the second sample value to the first sample value) may be the same as the amplification factor value for each detection channel previously stored in the memory (305).

[0083] On the other hand, if there is a problem in the analog circuit, and if an error occurs in the amplification of the measured value due to the problem, at least one of the ratios of the first sample value and the second sample value calculated from each detection channel may be different from the amplification factor value for each detection channel previously stored in the memory (305). Therefore, if there is a detection channel in which a value is calculated among the ratios of the calculated first sample value and the second sample value, that is, a value that is outside the error range, is different from the amplification factor value for each detection channel stored in the memory (305), the detection unit (303) can determine that there is a problem in the analog circuit.

[0084] FIG. 3 is a flowchart illustrating an operation process for determining whether an analog circuit part is abnormal by a protection device according to an embodiment of the present invention.

[0085] Referring to FIG. 3, a protection device according to an embodiment of the present invention can first measure the current or voltage of a system (10) by a measuring unit (301) (S300). The measuring unit (301) may be a CT (Current Transformer) that measures the current of the system (10) or a PT (Potential Transformer) that measures the voltage of the system (10).

[0086] When the above measuring unit (301) measures the current or voltage of the system (10), the analog measurement value measured by the measuring unit (301) can be input to the basic amplifier and channel amplifier of each detection channel. Then, the basic amplifier and channel amplifier of each detection channel can amplify the received analog measurement value according to a preset amplification factor (S302). Here, the amplification factor (basic factor) of the basic amplifier may be different for each detection channel, and the amplification factor of the channel amplifier may also be different for each detection channel. In this case, the amplification factor of the channel amplifier may be an integer multiple of the amplification factor (basic factor) of the amplification unit of the basic channel that is paired with the amplification channel, i.e., the basic amplifier, and the multiple (integer multiple) of the channel amplifier with respect to the basic factor may be different for each detection channel.

[0087] Then, the basic sampling unit and the channel sampling unit of each detection channel can perform sampling on the analog measurement values ​​amplified by the basic amplifier unit and the channel amplifier unit, respectively (S304). In this case, sampling can be performed according to the sampling rates set for each of the basic sampling unit and the channel sampling unit. In addition, the sampling rates of different detection channels (the sampling rate of the basic sampling unit and the sampling rate of the channel sampling unit) can be different for each detection channel.

[0088] In this case, the sampling speed of each detection channel (the sampling speed of the basic sampling unit and the sampling speed of the channel sampling unit) may be faster than the sampling speed at which the protection device acquires samples for calculating current or voltage values ​​to determine whether there is an abnormality in the system. Alternatively, if the detection unit (303) uses a sample acquired from the basic channel of any one of the plurality of detection channels to determine whether there is an abnormality in the analog circuit unit and to calculate the current or voltage value of the system at the same time, the sampling speeds of the remaining detection channels excluding the corresponding detection channel (e.g., the first detection channel) may be faster than the sampling speed of the first detection channel.

[0089] In this way, by making the sampling speed of at least one detection channel for detecting whether there is an abnormality in the analog circuit faster than the sampling speed at which the protection device acquires samples for calculating the current or voltage value of the system, it is possible to first detect whether there is an abnormality in the analog circuit before determining whether there is an accident in the system from the current or voltage value of the system.

[0090] With reference to FIGS. 4a and 4b below, we will examine in more detail an example of how to detect abnormalities in an analog circuit section according to a sampling rate before overcurrent or overvoltage occurs in the system.

[0091] Meanwhile, in step S304, samples obtained from analog measurement values ​​amplified by the connected amplifiers, i.e., each basic amplifier and channel amplifier, according to the sampling rate set by the basic sampling unit and the channel sampling unit of each detection channel can be input to the ADC (302). In addition, the ADC (302) can convert the samples obtained from the basic channel and the amplification channel of each detection channel, i.e., the sample values, into digital measurement values ​​(S306).

[0092] Then, the detection unit (303) calculates the ratio of the digital measurement value of the basic channel and the digital measurement value of the amplification channel for each detection channel converted by the ADC (302), and can calculate the ratio of the digital measurement value of the amplification channel to the digital measurement value of the basic channel for each detection channel, i.e., the amplification factor of the amplification channel (S308).

[0093] And the detection unit (303) can compare the amplification factor calculated for each detection channel with the amplification factor for each detection channel previously stored in the memory (305). And as a result of the comparison, it can detect whether there is a detection channel in which the difference between the amplification factor for each detection channel previously stored in the memory (305) and the amplification factor for each detection channel calculated in step S308 is outside the preset error range (S310).

[0094] Here, the amplification multiplier for each detection channel is a ratio of the digital measurement value of the amplification channel to the digital measurement value of the basic channel set for each detection channel, and may be an amplification multiplier of the amplification channel to the amplification multiplier (basic multiplier) of the basic channel.

[0095] If, as a result of the detection in step S310, there is no detection channel in which the difference between the amplification multiplier for each detection channel previously stored in the memory (305) and the amplification multiplier for each detection channel calculated in step S308 exceeds the preset error range, the detection unit (303) can determine that there is no abnormality in the analog circuit. Accordingly, by proceeding to step S300 again and performing the following process again, it is possible to detect whether there is an abnormality in the analog circuit.

[0096] On the other hand, if, as a result of the detection in step S310, there is no detection channel in which the difference between the amplification multiplier for each detection channel previously stored in the memory (305) and the amplification multiplier for each detection channel calculated in step S308 exceeds the preset error range, the detection unit (303) may determine that there is an abnormality in the analog circuit. Then, the detection unit (303) may notify a preset server or terminal of an alarm related to the detected abnormality in the analog circuit through a preset communication means, for example, a wireless communication means or a wired communication means (S312).

[0097] In this case, the step S312 may further include a process of controlling a blocking unit (not shown) to perform a trip operation to block a load connected to the protection device from the system according to the control of the server or terminal or according to the detection result of the step S310.

[0098] Meanwhile, according to the above-described explanation, it has been mentioned that by making the sampling speed of the detection channel faster than the speed at which the protection device samples samples to calculate the current and voltage of the system, it is possible to detect an abnormality in the analog circuit before determining whether there is overcurrent or overvoltage based on the results of calculating the current and voltage of the system.

[0099] With reference to FIGS. 4a and 4b below, we will examine in more detail how the time it takes for an analog circuit abnormality to be detected varies depending on the sampling rate.

[0100] First, Fig. 4a is an example diagram showing the point in time at which sampling is performed when the sampling rates are different.

[0101] Referring to Fig. 4a, Fig. 4a (b) illustrates an example in which sampling is performed at a sampling speed 4 times faster than Fig. 4a (a). For example, if the sampling speed of Fig. 4a (a) is a speed at which 32 samples are acquired in one cycle (32 samples / cycle), Fig. 4a (b) may illustrate an example in which sampling is performed at a speed at which 128 samples are acquired in one cycle (128 samples / cycle). In this case, as shown in Fig. 4a, the slower the sampling speed, the longer the interval between the points in time at which sampling is performed, i.e., the sampling interval.

[0102] Meanwhile, sampling must be performed at the time when an error occurs due to an abnormality in the analog circuit, so that an abnormality in the analog circuit can be detected from the sample value. Therefore, the size of the sampling interval can determine the precision of detecting an abnormality in the analog circuit.

[0103] FIG. 4b is an exemplary diagram showing an example in which an error value is detected due to an abnormality in an analog circuit based on samples sampled at different sampling rates.

[0104] First, when an abnormality occurs in the analog circuit, the abnormal phenomenon in the analog circuit may intermittently repeat in a state of occurring for a short time and then being restored again. Accordingly, the abnormal phenomenon in the analog circuit may occur in a pulse form as shown in (a) and (b) of Fig. 4b. Accordingly, the abnormal phenomenon in the analog circuit may occur as in the time intervals (501 to 504) shown in (a) and (b) of Fig. 4b. (a) and (b) of Fig. 4b assume that the abnormal phenomenon occurs within the time it takes for an average of 4 samples to be sampled when sampling is performed at a rate of 128 samples / cycle.

[0105] First, referring to (a) of Fig. 4b, if sampling is performed at 32 samples / cycle, an example in which an abnormality in the analog circuit according to the above-described assumption occurs will be examined. Even if an error occurs due to the first abnormality in the analog circuit, since the sampling points do not overlap, a sample value within the normal range can be sampled. Accordingly, the abnormality in the analog circuit may not be detected. Similarly, even if the second and third errors occur, the abnormality in the analog circuit may not be detected. However, during the time (504) in which the fourth error occurs, the points in time at which the sample (511) is sampled may overlap. Therefore, in the case of (a) of Fig. 4b, the detection unit (303) can detect an abnormality in the analog circuit through the sample (511) including the amplification value due to the error. In this case, assuming that 1 cycle is 32 seconds, in the case of (a) of Fig. 4b, the detection unit (303) can detect an abnormality in the analog circuit after three sampling intervals have elapsed, and thus, can detect an abnormality in the analog circuit after three seconds have elapsed.

[0106] On the other hand, referring to (b) of FIG. 4b, if sampling is performed at 128 samples / cycle, an example in which an error occurs due to an abnormality in the analog circuit according to the above-described assumption will be examined. The points in time at which samples (521, 522, 523, 524) are sampled may overlap with the times (501 to 504) at which an error due to an abnormality in the analog circuit occurs. Therefore, in a case such as (b) of FIG. 4b, the detection unit (303) can detect an abnormality in the analog circuit through any one of the samples (521, 522, 523, 524) including an amplification value due to the error.

[0107] In this case, the detection unit (303) can detect an abnormality in the analog circuit from the sample (521) that is sampled first among the samples (521, 522, 523, 524) that include an error amplification value due to an abnormality in the analog circuit. In this case, assuming that 1 cycle is 32 seconds, as in (a) of Fig. 4b, the detection unit (303) in (b) of Fig. 4b can detect an abnormality in the analog circuit when two sampling periods have elapsed, and thus can detect an abnormality in the analog circuit when 1.5 seconds have elapsed.

[0108] In this case, it is assumed that the speed at which the detection unit (303) samples the sample to determine the state of the system through the current or voltage of the system is 32 samples / cycle as in (a) of the above-described FIG. 4b, and it can be assumed that the sampling speed of the detection channel provided in the protection device according to the embodiment of the present invention is 128 samples / cycle as in (b) of the above-described FIG. 4b.

[0109] In this state, when an abnormality in the analog circuit occurs as shown in (a) and (b) of Fig. 4b, the time point at which the abnormality in the analog circuit can be detected at a sampling rate of 32 samples / cycle may be the time point at which the sample (511) that has been misampled due to the abnormality in the analog circuit is sampled in (a) of Fig. 4b. On the other hand, the time point at which the abnormality in the analog circuit can be detected at a sampling rate of 128 samples / cycle may be the time point at which the sample (521) that has been misampled for the first time due to the abnormality in the analog circuit is sampled in (b) of Fig. 4b.

[0110] Therefore, the faster the sampling rate, the faster the detection of anomalies in the analog circuit. Therefore, in order to detect anomalies in the analog circuit before the system current or voltage is miscalculated due to anomalies in the analog circuit, the sampling of the detection channel must be performed at a faster rate than the sampling rate for calculating the system current or voltage.

[0111] Therefore, the sampling rate of the detection channel, i.e., the sampling rate of the basic sampling unit and the sampling rate of the channel sampling unit, may be faster than the sampling rate for calculating the current or voltage of the system to determine the status of the system. In addition, as shown in Fig. 2b, when the detection channels are configured in multiple numbers, the sampling rate of at least one detection channel may be faster than the sampling rate for calculating the current or voltage of the system.

[0112] Meanwhile, a protection device according to an embodiment of the present invention may include a plurality of detection channels having a sampling rate higher than a sampling rate for calculating a current or voltage of a system, as shown in FIG. 2B. In addition, the sampling rate of each detection channel may be different for each detection channel. Here, the protection device may deactivate some of the detection channels having different sampling rates depending on either the detection unit (303) or the ADC (302) or the hardware specifications of the load or system to which the protection device is connected.

[0113] For example, if either the detection unit (303) or the ADC (302) or the hardware performance such as the load is sufficient, all detection channels can be activated. In this case, the amplification ratio corresponding to each detection channel can be calculated through the values ​​of the amplification samples of each detection channel sampled at different sampling rates and the amplification samples of the detection channel with the default amplification ratio (e.g., the channel with the minimum amplification ratio (e.g., the first detection channel)). Then, the amplification channels for each detection channel calculated and the amplification channels for each detection channel previously stored in the memory (305) can be compared to determine whether there is an error for each detection channel.

[0114] In this case, since the sampling rates of each detection channel are different and may be inversely related to each other, abnormalities in the analog circuit can be detected through each of the different, non-overlapping sampling rates. Therefore, the detection accuracy for detecting abnormalities in the analog circuit can be improved.

[0115] However, in this case, since the number of samples sampled for the same time period for each detection channel increases significantly, the load on the detection unit (303) or ADC (302) may increase. Accordingly, at least one of the detection channels may be limited depending on the hardware performance of the detection unit (303) or ADC (302) or the load or system. In this case, at least one detection channel may be activated except for the detection channel whose amplification ratio is the default ratio, and the remaining detection channels may be deactivated. In addition, the detection unit (303) may calculate and compare the amplification ratios for only the activated channels.

[0116] Meanwhile, the protection device according to an embodiment of the present invention can determine whether there is an abnormality in an analog circuit for measuring current or voltage of different phases of a system by dividing the plurality of detection channels. To this end, the protection device can group the plurality of detection channels by phase of the system, and for each group, the current or voltage of each phase can be amplified and a sample value sampled from the amplified current or voltage can be compared with the sample value of the basic detection channel (a detection channel whose amplification magnification is the basic magnification) of each group. In addition, the amplification magnification can be calculated for each detection channel to individually determine an abnormality in the analog circuit corresponding to each phase.

[0117] FIG. 5 is a flowchart illustrating an operation process in which a protection device according to an embodiment of the present invention determines whether there is an abnormality in an analog circuit for each phase of a system.

[0118] Referring to FIG. 5, the detection unit (303) of the protection device according to an embodiment of the present invention can assign at least one different detection channel to each phase of the system (S500). In this case, if the system is a three-phase, four-wire AC system, each phase can be phase A, phase B, and phase C according to phase, and may further include phase N and ZCT. In addition, at least one detection channel can be assigned to each phase.

[0119] Here, the detection unit (303) can assign at least one detection channel to each phase. For example, if one detection channel is assigned, the assigned detection channel can be a basic detection channel (e.g., a first detection channel) with a basic sampling rate set for detecting a current or voltage of a specific phase, i.e., the assigned phase.

[0120] In this case, the basic detection channel may include a basic channel including a basic amplifier unit in which a basic magnification for detecting the current or voltage of the assigned phase is set, and a basic sampling unit that performs sampling at the basic sampling rate from the current or voltage amplified at the basic magnification, and an amplification channel including a channel amplifier unit that amplifies the current or voltage of the assigned phase by an integer multiple of the basic magnification, and a channel sampling unit that performs sampling at the basic sampling rate from the current or voltage amplified by the channel amplifier unit.

[0121] Therefore, in the case of a phase to which one basic detection channel is allocated, the measurement of the current or voltage of the specific phase and the presence or absence of an abnormality in the analog circuit related to the current or voltage of the specific phase can be determined simultaneously according to the basic sampling rate.

[0122] Meanwhile, the detection unit (303) may assign at least one more detection channel to a specific phase in addition to the basic detection channel in order to detect whether there is an abnormality in the analog circuit related to the current or voltage in the specific phase. In this case, the detection channel assigned in addition to the basic detection channel may have a sampling speed of the basic sampling unit and the channel sampling unit that is faster than the basic sampling speed. Therefore, before the current and voltage of the specific phase due to the abnormality in the analog circuit are mismeasured, the abnormality in the analog circuit can be detected first through the at least one detection channel assigned in addition to the basic detection channel.

[0123] If at least one detection channel is allocated to each phase in the above step S500, the measuring unit (301) can measure current or voltage for each phase. In addition, the amplifiers of at least one detection channel allocated to each phase can amplify the measurement result of the current or voltage of the phase allocated to them at a preset magnification, i.e., the basic magnification (basic amplifier unit of each detection channel) or an amplification magnification according to an integer multiple of the basic magnification (channel amplifier unit of each detection channel) (S504).

[0124] In the above step S504, when the amplifier (basic amplifier, channel amplifier) ​​of each detection channel amplifies the measurement value, the sampling unit (basic sampling unit, channel sampling unit) of each detection channel can sample the amplified measurement value at a sampling rate assigned to each detection channel (S506). Then, the samples sampled from the sampling units (basic sampling unit, channel sampling unit) of each detection channel can be input to the ADC (302) and converted into digital measurement values ​​(S508).

[0125] Meanwhile, each digital measurement value converted by the ADC (302) can be input to the detection unit (303). And, the detection unit (303) can compare the sample value of the basic channel with the sample value of the amplification channel for each detection channel to calculate the amplification magnification of the amplification channel for the basic magnification. In this case, if at least one more detection channel is allocated in addition to the basic detection channel for a specific phase, the amplification magnification of the amplification channel for the basic magnification can be further calculated for samples sampled according to at least one sampling rate different from the basic sampling rate in addition to the basic sampling rate set for the specific phase (S510).

[0126] Then, the detection unit (303) can compare the amplification ratios calculated for each detection channel with the preset amplification ratios for each detection channel stored in the memory (305). As a result of the comparison, an amplification ratio that falls outside the preset error range from the preset amplification ratios of each detection channel stored in the memory (305) can be detected (S512).

[0127] Meanwhile, if, as a result of the detection in step S512, the difference between the amplification magnifications pre-assigned to each detection channel corresponding to the preset amplification magnifications for each detection channel stored in the memory (305) is less than or equal to the preset error range, the detection unit (303) can determine that the analog circuit related to the current or voltage of each phase is operating normally. Then, the detection unit (303) can continuously compare the amplification magnifications of each detection channel with the pre-stored amplification magnifications without notifying whether the analog circuit is abnormal. Accordingly, the amplification magnification for the current or voltage value measured for at least one detection channel assigned to each phase in step S500 can be calculated and compared with the amplification magnifications pre-stored in the memory (305) in the order in which sampling was performed.

[0128] However, if, as a result of the detection in step S512, an amplification factor that is out of the preset error range compared to the amplification factor of the corresponding detection channel previously stored in the memory (305) among the amplification factors calculated from each detection channel, i.e., an amplification factor having an error exceeding the above error range, is detected, the detection unit (303) can detect a specific phase corresponding to the detection channel in which the amplification factor exceeding the error range was calculated (S514). In addition, an abnormality detection notification indicating an abnormality in an analog circuit related to the current or voltage of the detected phase can be notified to a preset server, system, or terminal (S516).

[0129] Here, step S516 may further include a trip operation process for controlling a blocking unit (not shown) to block the connection between the load and the system. In this case, the trip operation process may be performed according to a control signal received from the server or terminal. In this case, step S516 may further include an operation process for receiving a control signal from the server or terminal to control the blocking unit for the trip operation.

[0130] Meanwhile, the above description has mentioned that the protection device according to an embodiment of the present invention can increase the accuracy of detecting abnormalities in the analog circuit by detecting abnormalities in the analog circuit according to a plurality of different sampling rates. To this end, the above description has mentioned that it can have a plurality of detection channels with different sampling rates.

[0131] In this way, if the sampling rate of each sampling unit constituting the detection channel is configured to be variable, it is possible to more precisely detect whether there is an abnormality in the analog circuit according to different sampling rates based on samples according to multiple different sampling rates using only one or at least two detection channels. In this case, not only the sampling unit but also the amplification ratio of the amplification unit can be configured to be variable.

[0132] FIG. 6 is a block diagram illustrating the configuration of a protection device according to an embodiment of the present invention in which the sampling rate and amplification ratio of the basic channel and the amplification channel are formed to be variable.

[0133] Referring to Fig. 6, Fig. 6 illustrates a configuration of a protection device including one detection channel (600) including one basic channel (610) and one amplification channel (620). In this case, the basic amplification unit (611) and the channel amplification unit (621) may have magnifications determined according to the control of the control unit (603), and the basic magnification, which is the magnification of the basic amplification unit (611), and the amplification magnification, which is the magnification of the channel amplification unit (621), may be different from each other. In more detail, the amplification magnification may be determined as an integer multiple of the basic magnification.

[0134] Meanwhile, the sampling speed of the basic sampling unit (612) and the channel sampling unit (622) may be determined according to the control of the control unit (603). In this case, the sampling speed of the basic sampling unit (612) and the sampling speed of the channel sampling unit (622) may be the same. Therefore, if the sampling speed of the basic sampling unit (612) is changed, the sampling speed of the channel sampling unit (622) may also be changed according to the changed speed. In other words, the basic channel and the amplification channel constituting one detection channel may be channels that sample measured values ​​amplified at different magnifications at the same sampling speed.

[0135] Meanwhile, the control unit (603) can perform the function of the detection unit (206, 303) described in FIG. 2A or FIG. 2B. In addition, the control unit (603) can determine different amplification ratios of the basic amplifier unit and the channel amplifier unit, and store information on the determined amplification ratios of each amplifier unit in the memory (605). In addition, the control unit (603) can determine a common sampling rate of the basic sampling unit (612) and the channel sampling unit (622), and store the determined sampling rate in the memory (605).

[0136] And when the measuring unit (601) measures the current or voltage of the system (10), the basic amplifier unit (611) and the channel amplifier unit (621) can be controlled to amplify the measurement results of the measuring unit (601) with different amplification factors, respectively. And the basic sampling unit (612) and the channel sampling unit (622) can be controlled to acquire samples at the same sampling rate for each of the amplification results of the basic amplifier unit (611) and the channel amplifier unit (621). Then, the values ​​of the samples at the same sampling rate for the measurement values ​​amplified at different amplification factors by the control unit (603) can be digitized in the ADC (602), respectively.

[0137] Then, the control unit (603) can compare the digitized sample values ​​in the ADC (602) to calculate the amplification ratio of the sample value of the amplification channel with respect to the sample value of the basic channel. Then, by comparing the calculated amplification ratio with the amplification ratio stored in the memory (605), it can check whether there is an abnormality in the analog circuit with respect to the sampling rate currently set in the basic sampling unit (612) and the channel sampling unit (622). And if there is an abnormality, that is, if the difference between the amplification ratio of the sample value of the amplification channel with respect to the sample value of the basic channel and the amplification ratio stored in the memory (605) exceeds a preset error range, notification information indicating the occurrence of an abnormality in the analog circuit can be notified to a preset server or terminal.

[0138] Meanwhile, if the difference between the amplification factor of the sample value of the amplification channel for the sample value of the basic channel and the amplification factor stored in the memory (605) is within a preset error range, the control unit (603) can change the sampling rate currently set in the basic sampling unit (612) and the channel sampling unit (622). For example, the control unit (603) can gradually increase or decrease the sampling rate. In addition, the difference between the amplification factor calculated according to the sample value of the amplification channel for the sample value of the basic channel sampled according to the changed sampling rate and the amplification factor stored in the memory (605) can be calculated to detect whether there is an abnormality in the analog circuit according to the changed sampling rate.

[0139] By varying the sampling rate of the basic sampling unit (612) and the sampling rate of the channel sampling unit (622) in this way, it is possible to determine whether there is an abnormality in the analog circuit according to different sampling rates without requiring multiple detection channels with different sampling rates.

[0140] In addition, the control unit (603) may make the minimum sampling rate that can be set in the basic sampling unit (612) and the channel sampling unit (622) faster than the sampling rate at which samples for measuring the voltage or current of the system (10) are sampled, thereby allowing an abnormality in the analog circuit unit to be detected before an erroneous measurement of the voltage or current of the system (10) occurs due to an abnormality in the analog circuit unit.

[0141] Meanwhile, FIG. 7 is a flowchart illustrating the operation process of a control unit (603) that changes the sampling rate and determines whether there is an abnormality in the analog circuit unit in the protection device according to the embodiment of the present invention illustrated in FIG. 6.

[0142] Referring to FIG. 7, the control unit (603) of the protection device according to an embodiment of the present invention can first set an initial sampling rate to the basic sampling unit (612) and the channel sampling unit (622) (S700). Here, the initial sampling rate may be the maximum rate or minimum rate among the sampling rates that can be set to the basic sampling unit (612) and the channel sampling unit (622). Here, the minimum sampling rate may be a rate faster than the rate at which a sample for measuring the current or voltage of the system (10) is sampled. In addition, the maximum sampling rate may be the maximum sampling rate that can be set to the basic sampling unit and the channel sampling unit.

[0143] For example, as the sampling rate increases, the number of samples sampled within one cycle increases, and thus, if there is a problem in the analog circuit, the probability of collecting samples that are misamplified due to the problem may increase. Accordingly, the problem in the analog circuit can be detected more quickly and precisely. However, as the sampling rate increases, the load on each sampling unit, i.e., the basic sampling unit (612) and the channel sampling unit (622), and the load on the control unit (603) that must calculate the amplification ratio from the samples and detect the presence of a problem may be increased.

[0144] On the other hand, as the sampling rate decreases, the number of samples sampled within one cycle decreases, so the load on the basic sampling unit (612), the channel sampling unit (622), and the control unit (603) can be reduced. However, the accuracy of detecting abnormalities in the analog circuit unit can be further reduced.

[0145] Accordingly, the control unit (603) can set the initial sampling speed to either the maximum speed or the minimum speed, depending on whether priority is given to detection accuracy or to reducing the load on the sampling units and the control unit (603).

[0146] In the above step S700, when the initial sampling rate is determined, the control unit (603) can amplify the measurement result of the measurement unit (601) through each of the basic channel and the amplification channel at a magnification (basic magnification or amplification magnification) set in the amplification unit of each channel. Then, the amplified measurement value in each amplification unit can be sampled through the sampling unit of each channel, and the sampled sample of each channel can be converted into a digital measurement value through the ADC (602) (S702).

[0147] And the control unit (603) can compare the digital measurement values ​​converted in the step S702 with each other to calculate the amplification ratio of the amplification channel, and compare the amplification ratio corresponding to the amplification channel for which the amplification ratio was calculated, which is stored in the memory (605), with the calculated amplification ratio. And it can check whether the difference exceeds the preset error range (S704).

[0148] And, if the difference between the amplification ratio calculated from the amplification channel and the amplification ratio stored corresponding to the amplification channel is outside the preset error range as a result of the check in step S704, the control unit (603) can determine that there is an abnormality in the analog circuit and can notify a preset server or terminal of an alarm indicating the abnormal state of the analog circuit (S718).

[0149] Here, the step S718 may include a step of automatically performing a trip operation to cut off the load from the system (10) simultaneously with a control signal received from the server or terminal, or the notification notification. In addition, the check value for changing the sampling rate accumulated up to now may be initialized (S720).

[0150] On the other hand, if the difference between the calculated amplification ratios does not exceed the error range as a result of the check in step S704, the control unit (603) can increase the check value for changing the sampling rate by a preset value (S706). Then, it can be checked whether the check value accumulated up to now is less than a preset reference value (S708). Then, if the check value accumulated up to now is less than the preset reference value as a result of the check in step S708, the control unit (603) can proceed to step S702 again. Therefore, step S702 of amplifying the measured value while maintaining the currently set sampling rate, performing sampling on the amplified measured value according to the currently set sampling rate, converting it into a digital measured value, and calculating the amplification ratio of the amplification channel based on the converted digital measured value, and step S704 of checking whether there is an abnormality in the analog circuit by comparing it with a pre-stored amplification ratio, can be performed again.

[0151] On the other hand, if the check result of the step S708 above shows that the check value accumulated up to the present is not less than the preset reference value, the control unit (603) can decrease or increase the sampling speed set for each sampling unit by a certain speed (S710).

[0152] For example, if the initial sampling rate set in step S700 is the maximum sampling rate, the control unit (603) may reduce the sampling rate in step S710. On the other hand, if the initial sampling rate set in step S700 is the minimum sampling rate, the control unit (603) may increase the sampling rate in step S710. Accordingly, the sampling rate may be changed in a direction that gradually decreases or in a direction that gradually increases over a certain period of time, i.e., whenever the accumulated check value reaches a preset reference value.

[0153] Meanwhile, the control unit (603) can control the sampling rate to decrease or increase within a preset maximum or minimum rate. To this end, the control unit (603) can check whether the decreased or increased sampling rate in step S710 is less than or exceeds the preset minimum sampling rate or the preset maximum sampling rate (S712). If, as a result of the check, the decreased or increased sampling rate in step S710 is less than or exceeds the preset minimum sampling rate or the preset maximum sampling rate, the preset initial sampling rate can be set again for each sampling unit (S714).

[0154] Meanwhile, if the check result shows that the reduced or increased sampling rate in step S712 is less than or equal to the preset minimum sampling rate or does not exceed the preset maximum sampling rate, or if the preset initial sampling rate is reset to each sampling unit in step S714, the control unit (603) may initialize the check values ​​accumulated up to now. Accordingly, after the sampling rate is changed, the sampling rate set in step S712 or step S714 may be maintained until the accumulated check value reaches the reference value.

[0155] Therefore, the protection device according to an embodiment of the present invention can sample the current or voltage measurement results of the system (10) amplified at different magnifications while changing the sampling rate. Accordingly, it is possible to check whether there is an abnormality in the analog circuit corresponding to the path from the amplified result measured by the measurement unit (601) to the input to the ADC (602) according to different sampling rates. In addition, the minimum value among the sampling rates set in the protection device is set to be faster than the sampling rate of the sample used to determine whether there is an abnormality in the system (10) according to the current or voltage of the system (10), thereby enabling whether there is an abnormality in the analog circuit to be determined before determining whether there is an abnormality in the system (10).

[0156] The present invention described above can be implemented as computer-readable code on a medium having a program recorded thereon. Computer-readable media include all types of recording devices that store data that can be read by a computer system. Examples of computer-readable media include hard disk drives (HDDs), solid state disks (SSDs), silicon disk drives (SDDs), ROMs, RAMs, CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, etc., and also include media implemented in the form of carrier waves (e.g., transmission via the Internet). In addition, the computer may include the detection unit (206 or 303) or the control unit (603). Therefore, the above detailed description should not be construed as limiting in all respects, but should be considered as illustrative. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are intended to be included in the scope of the present invention.

Claims

1. A measuring unit that measures the current or voltage of a system; A detection channel that amplifies the measurement results of the above-mentioned measuring unit with a preset basic magnification and an amplification magnification according to a multiple of the basic magnification, and detects a basic sample sampled from the result amplified with the basic magnification and an amplified sample sampled from the result amplified with the amplification magnification according to a preset sampling rate; and A power system protection device characterized by including a detection unit that calculates a magnification of a sample value of the amplified sample with respect to a sample value of the basic sample, compares the calculated magnification with the size of the previously stored amplification magnification, and determines whether a circuit part is abnormal based on the comparison result.

2. In the first paragraph, the detection channel, A basic channel including a basic amplifier unit that amplifies the measurement result of the above-mentioned measuring unit at the basic magnification, and a basic sampling unit that samples the basic sample from the measurement result amplified at the basic magnification according to the preset sampling rate; and, A power system protection device characterized by comprising an amplification channel including a channel amplification unit that amplifies the measurement result of the above-mentioned measuring unit with the amplification factor, and a channel sampling unit that samples the amplified sample from the measurement result amplified with the amplification factor according to the preset sampling rate.

3. In paragraph 1, The above power system protection device is, Equipped with multiple detection channels, The above multiple detection channels are, A power system protection device characterized in that the sampling rates for sampling the basic sample and the amplified sample are different channels.

4. In the third paragraph, the minimum speed among the different sampling speeds is A power system protection device characterized in that the power system protection device is faster than the speed at which a sample is sampled to determine whether the power system is abnormal based on the current or voltage of the power system.

5. In the first paragraph, the detection unit, A power system protection device characterized in that the sample value of the basic sample and the sample value of the amplified sample are converted into digital values ​​through an ADC (Analog Digital Converter), and the ratio of the sample value of the amplified sample to the sample value of the basic sample converted into a digital value is calculated.

6. In paragraph 3, Each of the above multiple detection channels, Each corresponds to a different phase of the above system, The above detection unit, A power system protection device characterized in that it detects whether there is an abnormality in at least one circuit component related to each phase of the system by comparing the sample values ​​of amplified samples with the sample values ​​of basic samples detected in detection channels corresponding to each phase and the sizes of previously stored amplified magnifications corresponding to each detection channel.

7. In paragraph 6, the different phases of the system are: Includes A phase, B phase, C phase, N phase and ZCT (Zero Current Transformer) phase. A power system protection device characterized in that at least one detection channel having a different sampling rate is allocated to each of the A phase, B phase, C phase, N phase and ZCT phase.

8. In paragraph 2, The above basic sampling unit and the above channel sampling unit are, It is a variable sampling unit that can change the sampling rate, The above detection unit, A power system protection device characterized in that the preset sampling rate set in the basic sampling unit and the channel sampling unit is changed according to preset conditions.

9. In paragraph 8, the detection unit, A power system protection device characterized in that, when the result of comparing the size of the calculated multiplier and the previously stored amplification multiplier shows that no abnormality in the circuit part is detected more than a preset number of times, the preset sampling rate is changed.

10. In paragraph 9, the detection unit, Change the above preset sampling rate within the range of maximum sampling rate and minimum sampling rate, The above minimum sampling rate is, The above power system protection device has a sampling rate that is faster than the rate at which it samples samples to determine whether the system is abnormal based on the current or voltage of the system. The above maximum sampling rate is, A power system protection device characterized in that the maximum sampling rate is determined according to the hardware performance of the power system protection device at a rate faster than the minimum sampling rate.

11. Step of measuring the current or voltage of the system; A step of amplifying the above measurement results by a preset basic magnification and an amplification magnification according to a multiple of the basic magnification; A step of detecting a basic sample sampled from a result amplified at the basic magnification according to a preset sampling rate and an amplified sample sampled from a result amplified at the amplification magnification; A step of digitizing the sample value of the above basic sample and the sample value of the above amplified sample; A step of calculating a ratio of a sample value of a digitized basic sample and a sample value of the amplified sample; and, A control method for a power system protection device, characterized by including a step of determining whether there is an abnormality in a circuit part related to the amplification based on whether the difference between the calculated magnification and the size of the previously stored amplification magnification is within a preset error range.

12. In the 11th paragraph, the step of detecting the amplified sample comprises: A control method for a power system protection device, characterized in that the method comprises a step of detecting a plurality of pairs of basic samples and amplified samples sampled at different sampling rates through a plurality of detection channels that detect the basic samples and amplified samples at different sampling rates, respectively.

13. In paragraph 12, the step of determining whether there is an abnormality in the circuit unit is: A control method for a power system protection device characterized by comprising a step of comparing the ratio of the basic sample value and the amplified sample value calculated for each pair of the basic sample and the amplified sample with the size of the amplification ratio assigned to each detection channel to determine whether there is an abnormality in the circuit part for each different sampling speed.

14. In paragraph 12, the minimum speed among the different sampling speeds is A control method for a power system protection device, characterized in that the power system protection device has a sampling speed that is faster than the speed at which the power system protection device samples samples to determine whether the power system is abnormal based on the current or voltage of the power system.

15. In paragraph 11, the step of determining whether there is an abnormality in the circuit unit is: A control method for a power system protection device, characterized in that when the accumulated number of times in which the abnormality of the circuit section has not been determined reaches a preset number, the preset sampling rate is changed.

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