Power monitoring device and power monitoring program

Abstract

The present invention provides a power monitoring device that will not miss demand overruns even if there is a time difference between the trading meter and the monitoring device. [Solution] The system includes a receiving unit 31 that receives pulses indicating the amount of power from a trading meter 2, a unit power calculation unit 32 that calculates the unit power used in the most recent minute, an integrated power calculation unit 33 that calculates the cumulative power used from 00 minutes before the start time of a predetermined contract period (30 minutes) until 1 minute before, a predicted power calculation unit 34 that calculates the predicted power if the unit power is used until 30 minutes before the end time of the contract period, and an excess determination unit 35 that determines whether the demand conversion value of the sum of the predicted power and the integrated power exceeds the alarm setting value. The integrated power calculation unit 33 and the predicted power calculation unit 34 perform a demand prediction calculation for each time period that has been shifted by 1 minute at a time until the shift amount reaches 30 minutes, and determine whether the calculated demand prediction value exceeds the alarm setting value.

Description

Technical Field

[0001] The present invention relates to a power monitoring device that monitors the amount of electric power used within a predetermined period.

Background Art

[0002] In low-voltage power reception (contract power < 50 kW) such as in ordinary households, the basic charge for electricity bills is a fixed charge according to the contract type with the power company, and there is no variation according to the amount of power used. On the other hand, in the case of high-voltage power reception (50 kW ≤ contract power < 500 kW) such as in companies and facilities, although there is no limit on the use of power according to the contract power, the largest value among the maximum demand powers for the current month and the past 11 months (the monthly maximum value of the average power consumption (kW) during that period in 30-minute units from 00 minutes to 30 minutes and from 30 minutes to 00 minutes per hour) becomes the contract power for the current month, and the basic charge varies accordingly. In the present disclosure, the average power consumption (kW) for 30 minutes is referred to as the 30-minute demand value, and the amount of power used (kWh) for 30 minutes can be converted to the average power (kW) for 30 minutes by doubling the value.

[0003] Once the basic charge for the contract power has increased, it will not decrease for one year. Therefore, when the maximum demand power is updated within one year, the basic charge for the contract power will increase from the current month. That is, the basic charge for the contract power is determined by the peak power consumption for just 30 minutes during the past year. Therefore, companies and facilities where the power consumption throughout the year is large only for a short period of time will pay an excessive basic charge.

[0004] As a technology for monitoring such peak power usage, for example, the technologies described in Patent Documents 1 to 3 have been disclosed. The technology described in Patent Document 1 consists of a power input unit that counts power pulses, a target power setting unit, an arithmetic processing unit that samples the counted power and calculates an integrated value within a predetermined time, calculates a predicted power amount from the integrated value and compares it with the target power, a storage unit that stores the integrated value, a clock unit that measures the current time, the demand time limit and the time of power sampling, and an alarm output unit that outputs an alarm signal if the predicted power amount exceeds the target value. The arithmetic processing unit is equipped with means for obtaining an approximate formula by the least squares method from multiple integrated values ​​within a predetermined time in the storage unit and calculating the predicted power value.

[0005] The technology described in Patent Document 2 provides a demand control system comprising: a first prediction value calculation means that calculates a first predicted value of demand power at a set time based on a moving average of power consumption calculated over a first time frame; a first determination means that compares the first predicted value with a target value of demand power and converts it into an index according to a specific determination criterion indicating the magnitude of power consumption; a second prediction value calculation means that calculates a second predicted value of demand power at a set time based on a moving average of power consumption calculated over a second time frame longer than the first time; a second determination means that compares the second predicted value with a target value and converts it into an index according to the determination criterion; and an overall determination means that, when determining whether or not to implement control to reduce the power consumption of the load, adds up the index converted from the first predicted value and the index converted from the second predicted value and compares them according to the determination criterion.

[0006] The technology described in Patent Document 3 is a device that adjusts the load to bring the amount of electricity used over a certain period of time closer to a target amount of electricity. The device has multiple reference power pattern data for a certain period of time, selects one reference power pattern data based on the date and the demand start time, and adjusts the load by comparing the amount of electricity used with this selected reference power pattern data. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2000-14003 [Patent Document 2] Japanese Patent Publication No. 2022-176835 [Patent Document 3] Japanese Patent Application Publication No. 03-195335 [Overview of the project] [Problems that the invention aims to solve]

[0008] In the case of a device that monitors peak power usage (30-minute demand value) as described above (hereinafter referred to as the demand monitoring device), the demand monitoring device calculates power usage by receiving power pulses measured by the power company's trading meter. However, there may be a discrepancy in the time displayed on the clocks of the trading meter and the demand monitoring device. If the time displayed on the trading meter and the demand monitoring device is out of sync, even if the demand monitoring device can accurately predict or measure power usage, it will be difficult to accurately determine whether the maximum demand power exceeds the contracted power in 30-minute intervals (00-30 minutes and 30 minutes-00 minutes) each hour. Furthermore, since the built-in clock of the trading meter is an independent clock using a crystal oscillator, it is difficult to synchronize their times even if the built-in clock of the demand monitoring device is a GPS clock.

[0009] The technologies described in Patent Documents 1 to 3 do not allow for accurate demand monitoring when there is a time difference between the trading instrument and the demand monitoring device, as described above.

[0010] Therefore, the present invention has been made to solve the above problems, and aims to provide a power monitoring device and a power monitoring program that can prevent demand overload from being overlooked even if there is a time difference between the power company's metering equipment and the demand monitoring device. [Means for solving the problem]

[0011] The power monitoring device disclosed herein includes: a receiving unit that receives pulse information relating to the amount of power transmitted from a power measuring instrument; a unit power calculation unit that calculates the amount of power used between the current time and a predetermined unit time before a predetermined unit time based on the pulse information as a unit power amount; an integrated power calculation unit that calculates the amount of power used between the start time of a predetermined contract period and the unit time based on the pulse information as an integrated power amount; and a predicted power calculation unit that calculates the integrated value of the amount of power if the unit power amount is used continuously until the end time of the contract period as a predicted power amount; and the predicted power amount and The system includes an excess determination unit that determines whether the demand-converted value of the total amount of electricity, including the cumulative amount of electricity, exceeds the contracted power for the contract period, which is pre-contracted. The cumulative amount calculation unit and the predicted amount calculation unit calculate the cumulative amount of electricity and the predicted amount of electricity for each shifted time period, while shifting the start and end times of the contract period by the unit time, until the shift amount reaches the size of the contract period. The excess determination unit then determines whether the demand-converted value of the total amount of electricity, including the predicted amount of electricity and the cumulative amount, exceeds the contracted power for each shifted time period.

[0012] Thus, in the power monitoring device disclosed in this application, the start and end times of the contract period are shifted by unit hours, and the cumulative power and predicted power are calculated for each shifted time period until the shifted amount reaches the contract period, that is, until the time shifted by the contract period from the current time. In order to determine whether the demand-converted value of the total power exceeds the contracted power, even if there is a discrepancy between the time of the trading meter and the time of the power monitoring device, it is possible to determine the maximum demand power considering the entire time axis for each unit hour within the contract period, thereby preventing demand overruns. [Brief explanation of the drawing]

[0013] [Figure 1] This is a system configuration diagram of a power monitoring system including a power monitoring device according to the first embodiment of the present invention. [Figure 2]This is an explanatory diagram illustrating an example of an alarm failure in a conventional demand monitoring device when there is a time difference between the device and the trading instrument. [Figure 3] This is a functional block diagram showing the configuration of a power monitoring device according to the first embodiment of the present invention. [Figure 4] This is an explanatory diagram illustrating the processing of a power monitoring device according to the first embodiment of the present invention. [Figure 5] This is a flowchart showing the operation of a power monitoring device according to the first embodiment of the present invention. [Figure 6] This is a functional block diagram showing the configuration of a power monitoring device according to a second embodiment of the present invention. [Figure 7] This is a flowchart showing the operation of the suppression control unit in a power monitoring device according to a second embodiment of the present invention. [Figure 8] This figure shows an example illustrating the processing of a suppression control unit in a power monitoring device according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0014] (First embodiment of the present invention) The power monitoring device according to this embodiment will be described with reference to Figures 1 to 5. The power monitoring device according to this embodiment calculates the amount of electricity used per predetermined time based on power pulses measured by the power company's metering equipment, and outputs a warning if the predicted value exceeds the contracted power.

[0015] FIG. 1 is a system configuration diagram of a power monitoring system including the power monitoring device according to the present embodiment. The power monitoring system 1 includes a metering instrument 2 of an electricity company with whom a contract is made, which is attached to a pole on the premises or power receiving equipment 8 installed within a company or facility, a pulse receiving amplifier 3 that receives a power pulse from the metering instrument 2, amplifies and shapes it internally, and transmits it to the power monitoring device 10, a power monitoring device 10 that performs various calculations based on the power pulse signal sent from the pulse receiving amplifier 3 and monitors power in real time, a system management device 4 installed with software that can at least refer to the calculation content of the power monitoring device 10, a log management device 5 that displays and stores information such as the calculation results of the power monitoring device 10, and a rotating lamp 6 that outputs a warning based on the calculation results of the power monitoring device 10.

[0016] The metering instrument 2 transmits a pulse corresponding to the power measured by a power pulse CT 2a installed inside, to the pulse receiving amplifier 3 via a sensor cable 7. The pulse receiving amplifier 3 amplifies and shapes the received power pulse into a pulse that can be received by the power monitoring device 10. The pulse amplified and shaped by the pulse receiving amplifier 3 is transmitted by an amplifier cable 9 and input to the power monitoring device 10.

[0017] The power monitoring device 10 has an internal computer (for example, a computer that generally known CPU, MPU and other arithmetic processing units, memories such as RAM and ROM, storage devices such as hard disks, input / output interfaces, communication interfaces, etc. cooperate to execute processing) perform arithmetic processing such as, for example, current power consumption value, demand prediction value and demand integrated value updated every unit time (here, 1 minute), and output of multiple types of alarms, based on the input pulse signal. The result of the alarm output is transmitted to the rotating lamp 6, and the rotating lamp 6 is driven according to the type of the alarm. Also, the power monitoring device 10 is supplied with driving power by connecting an AC power cord 10a to a commercial power supply of AC 100V.

[0018] The log management device 5 allows the internal computer to acquire and manage information such as the information of the pulse signal input to the power monitoring device 10 and the results calculated by the computer of the power monitoring device 10 as log data, and use it for analysis as needed.

[0019] The system management device 4 has an internal computer similar to the above, and is a device such as a personal computer or a tablet installed with demand monitoring software for monitoring demand by referring to various information in the power monitoring device 10, and can communicate with the power monitoring device 10 by wire or wirelessly. For example, the system management device 4 can perform demand data management such as displaying the current time indicated by the built-in clock of the power monitoring device 10, the current power consumption value, the demand prediction value, the demand graph, etc., acquiring demand data, and outputting a report of demand data.

[0020] Hereinafter, the power monitoring device 10 will be described in more detail. As described above, in the conventional demand monitoring device, it is assumed that there is no time difference between the built-in clock of the metering instrument 2 and the built-in clock of the demand monitoring device. Since the built-in clocks in each device are independent clocks, even if the time is synchronized initially, the time may deviate due to various factors.

[0021] This section describes an example of an alarm failure that occurs when there is a time difference between the demand monitoring device and the trading instrument 2. Figure 2 is an explanatory diagram illustrating an example of an alarm failure in a conventional demand monitoring device when there is a time difference with the trading instrument. In Figure 2, the solid line graph axis (A) represents the demand time measured by the demand monitoring device, and is also the demand time of the trading instrument 2, which has no time difference with the demand monitoring device. The dashed line graph axis (B) represents the demand time when the time of the trading instrument 2 is 5 minutes ahead of the demand monitoring device, and the dashed line graph axis (C) represents the demand time when the time of the trading instrument 2 is 5 minutes behind the demand monitoring device. In Figure 2, the vertical axis of the graph is the value obtained by aggregating the number of measured pulse signals every minute and converting it into a demand value (demand increase value per minute), and the line connecting these values ​​is hereinafter referred to as the demand curve.

[0022] As shown in the demand curve in Figure 2, during a demand period, demand increases as time progresses. The demand monitoring device predicts whether the predicted demand value, which lies on the extension of the demand curve, will exceed the contracted power (i.e., the alarm setting value that triggers an alarm) in 30-minute intervals (00 minutes → 30 minutes, 30 minutes → 00 minutes), and outputs an alarm if it does. The demand value prediction determination in Figure 2 is based on whether the predicted demand value will exceed the alarm setting value if the increase in the demand value over the most recent minute continues until the 30-minute or 00-minute mark.

[0023] As shown by the solid line A in Figure 2, in a demand period where there is no time difference between the demand monitoring device and the trading meter 2, the demand monitoring device determines whether the predicted demand value, which is the sum of the cumulative demand value over the past 16 minutes and the predicted demand value assuming that the demand increase value for the most recent minute from 16 to 17 minutes continues for the remaining 13 minutes, will ultimately exceed the alarm setting value, which is the contracted power, at the current time t (let's assume t = 17 minutes). In the example in Figure 2, the predicted demand value at 30 minutes of the demand period represented by solid line A with the current time as t does not exceed the alarm setting value, so no alarm is output, and even if this condition continues, there will be no demand overrun within the demand period represented by solid line A.

[0024] As shown by the dashed line B in Figure 2, in a demand timeout where the time on the trading meter 2 is 5 minutes ahead of the state indicated by the solid line A, if the demand increase value for the most recent minute remains unchanged, the trading meter 2 will detect an excess demand, the maximum demand power will be updated, and the basic charge for the contracted power will increase. At this time, the demand monitoring device is in the measurement state of the solid line A described above, so no alarm is output.

[0025] As shown by the dashed line C in Figure 2, in a demand timeout where the time on the trading meter 2 is 5 minutes behind the state indicated by the solid line A, if the demand increase over the most recent minute continues, the trading meter will detect an excess demand, the maximum demand power will be updated, and the basic charge for the contracted power will increase. At this time, the demand monitoring device is in the state indicated by the solid line A, so no alarm is output.

[0026] Thus, if there is a time difference between the trading instrument 2 and the demand monitoring device, the decision on whether or not to issue an alarm will differ. Conventional demand monitoring devices do not take such time differences into account, so there are cases where an alarm for exceeding demand is not issued. If the time difference between the built-in clock of the trading instrument 2 and the built-in clock of the demand monitoring device is as shown by the dashed line B and the dashed line C in Figure 2, the warning that should have been issued will not be detected, and the demand monitoring device will not be able to make an appropriate judgment.

[0027] In this embodiment, the power monitoring device 10 is capable of reliably outputting an alarm without missing demand overload, even when there is a time difference between the trading meter 2 and the power monitoring device 10, as shown in Figure 2.

[0028] Figure 3 is a functional block diagram showing the configuration of the power monitoring device according to this embodiment. The computer of the power monitoring device 10 includes a receiving unit 31 that receives pulse information relating to the amount of power transmitted from the trading meter 2, which is a power measuring instrument, via a pulse receiving amplifier 3 and stores it in a data storage unit 40; a unit power amount calculation unit 32 that calculates the amount of power used between the current time t and the time t-1 a unit time prior, based on the pulse information stored in the data storage unit 40, as a unit power amount; an integrated power amount calculation unit 33 that calculates the amount of power used between the start time of a predetermined contract period registered in the data storage unit 40 and the time t-1, as an integrated power amount, based on the pulse information stored in the data storage unit 40; a predicted power amount calculation unit 34 that calculates the integrated value of the amount of power if the unit power amount is used continuously until the end time of the contract period, as a predicted power amount; and an excess determination unit 35 that determines whether the demand conversion value of the sum of the predicted power amount and the integrated power amount exceeds the contracted power (alarm setting value) per contract period that has been contracted in advance.

[0029] In the following explanation, the unit time will be set to 1 minute. The predetermined contract period agreed upon with the power company is generally in 30-minute increments, and this 30-minute period will be defined as the period from 00 minutes to 30 minutes past the hour and from 30 minutes past the hour to 00 minutes past the hour. The contracted power is determined in accordance with the contract concluded between the power company and the consumer, and if the 30-minute demand value exceeds the contracted power (alarm setting value) even once, the basic contract fee for the following month and the following year will be renewed to a higher amount. The power monitoring device 10 outputs a warning in advance if it is predicted that the demand-converted value of the amount of electricity used over 30 minutes (i.e., the average power (kW) over 30 minutes, which is equivalent to twice the amount of electricity used over 30 minutes (kWh)) will exceed the contracted power (alarm setting value). Based on these premises, the processing of the power monitoring device 10 will be explained in detail.

[0030] Figure 4 is an explanatory diagram illustrating the processing of the power monitoring device according to this embodiment. The processing of the power monitoring device 10 will be explained with reference to Figure 4, along with the processing details of each processing unit in Figure 3. Note that the demand curve shown in Figure 4 (a graph showing the change in the amount of power consumed aggregated every minute) is shown as a straight line (to show a monotonically increasing over time due to a fixed load) for the sake of clarity in the explanation.

[0031] In Figure 4, we assume a standard 30-minute demand period with the current time t as the demand monitoring start time. If the demand monitoring start time is t=1, the standard 30-minute demand period is assumed to be the state where the current time t is 1 minute after the start time of the contract period (00 minutes), i.e., the state where pulse information from 00 minutes to 01 minutes has been acquired. Note that in Figure 4, the calculation exclusion period described later is taken into consideration, so the demand monitoring start time is t=10, and the period based on the zero point at t=10 is shown as the standard 30-minute demand period.

[0032] In this embodiment, since it is necessary to consider the time difference between the trading meter 2 and the power monitoring device 10, the time axis of the standard 30-minute demand period is shifted back by one minute at a time, and a demand period is constructed using pulse information up to the past 30 minutes. In other words, a demand period is constructed where the current time t is 1 minute after the start time of the contract period (00 min), so t=1; a demand period is constructed where the current time t is 2 minutes after the disclosure time of the contract period (00 min), so t=2; and so on, with the current time t sequentially elapsed from 1 minute to 30 minutes after the start time of the contract period (00 min). This allows the power monitoring device 10 to cover all demand prediction calculation patterns, regardless of where the time currently measured by the trading meter 2 is within the 30-minute demand period.

[0033] Here, we will explain the calculation exclusion period shown in Figure 4. The more data used to perform demand forecasting, the higher the accuracy; the fewer data points, the lower the accuracy. For example, if the current time t is 5 minutes after the start time of the contract period (00 minutes), the predicted demand value at 30 minutes, the end time of the contract period, will be calculated from the pulse information obtained from 00 minutes to t=5. In contrast, if t is 25 minutes after the start time (00 minutes), the predicted demand value at 30 minutes, the end time of the contract period, will be calculated from the pulse information obtained from 00 minutes to t=25. In other words, in the latter case, short-term predictions are made based on a large amount of pulse information, making it possible to perform prediction calculations with a certain degree of accuracy. On the other hand, in the former case, long-term predictions are made based on a small amount of pulse information, resulting in lower accuracy of the prediction calculations.

[0034] Furthermore, if the time currently being measured by trading instrument 2 is relatively early in the 30-minute demand period of the trading instrument 2's internal clock, there is ample time remaining before trading instrument 2 detects a demand overrun. For example, if the internal clock time of trading instrument 2 is t=5, there are 25 minutes remaining before a demand overrun is detected, so it may not be desirable to use the demand forecast value for this period.

[0035] Therefore, in the power monitoring device 10 according to this embodiment, in order to prevent the deterioration of accuracy as described above, a calculation exclusion period is set in advance, during which the calculation of demand prediction is excluded from the period from the start time of the contract period (00 minutes) until a predetermined time has elapsed. The calculation exclusion period can be set in advance by the user of the power monitoring device 10 and is registered in the data storage unit 40 by the calculation exclusion period setting means (not shown). In Figure 4, since the demand monitoring start time is set to 10 minutes, the calculation exclusion period is 9 minutes, which is 10 minutes minus 1. In other words, for the demand period from the start time of the contract period (00 minutes) to 9 minutes, there is little pulse information to predict the demand, so the accuracy of the demand prediction calculation may deteriorate. Furthermore, even if the predicted value at an early time exceeds the demand excess level, there is time to spare before it actually exceeds the level, so the demand prediction calculation is not performed. As a result, in the example in Figure 4, when using data from the past 30 minutes, a demand period from t=10 to t=30 is constructed, excluding the past 10 minutes.

[0036] As shown in Figure 4, the power monitoring device 10 shifts the time axis of the demand time periods one minute into the past, starting from the current time t which is set as the demand monitoring start time (reference 30-minute demand time period). It then performs demand prediction calculations for each demand time period in the past 30 minutes, using the start time 00 minutes, which is the start time of each demand time period, as the reference. In the example in Figure 4, the demand prediction calculation is performed for the demand time periods from t=10 to t=30, excluding the calculation exclusion period. The demand prediction value for each time period is calculated as a demand prediction candidate value, and the maximum value among these demand prediction candidate values ​​is taken as the demand prediction value at the current time t.

[0037] In the example shown in Figure 4, the demand curve is represented as a straight line, as described above, so the predicted demand value for each time period is the same. However, in reality, the slope of the demand curve changes moment by moment, so different predicted demand values ​​will be calculated for each time period.

[0038] Then, when one minute has passed from the current time t, the latest pulse information for the last minute is added to the demand curve, and a new 30-minute demand period is assumed, with the current time t=t+1 as the demand monitoring start time.

[0039] The above demand prediction calculation is performed by the processing units shown in Figure 3. In Figure 3, pulse information regarding the amount of electricity measured by the trading meter 2 is received by the receiving unit 31 via the pulse receiving amplifier 3 and stored entirely in the data storage unit 40. In addition to the measured pulse information, the data storage unit 40 also contains setting information necessary for the demand prediction calculation as explained in Figure 4, such as the amount of electricity equivalent to one pulse, unit time (1 minute), contract period (30 minutes), contract power, and calculation exclusion period (10 minutes).

[0040] The unit energy calculation unit 32 calculates the power consumption (unit energy) from the number of pulses in the most recent minute, based on the pulse information stored in the data storage unit 40. That is, it calculates the power consumption for the most recent minute by totaling the number of pulses received between time t-1 and the current time t.

[0041] The predicted power consumption calculation unit 34 calculates the cumulative power consumption (predicted power consumption) for each demand period, assuming that the latest 1-minute unit power consumption calculated by the unit power consumption calculation unit 32 is used continuously until the end of the contract period, which is 30 minutes or 00 minutes. In other words, the predicted power consumption is calculated for each demand period, assuming that time t progresses sequentially from 00 minutes into the contract period, from 1 minute to 30 minutes, in 1-minute increments. In the example in Figure 4, the predicted power consumption is calculated for each demand period that has been shifted back in time by 1 minute from t=10 to t=30, excluding the calculation exclusion period.

[0042] The integrated energy calculation unit 33 calculates the integrated energy amount (integrated energy amount) for each demand period, based on the pulse information stored in the data storage unit 40, from the start time of the contract period (00 or 30 minutes) to one minute before time t. In the example in Figure 4, for each demand period shifted by one minute from t=10 to t=30, the integrated energy amount is calculated from the start time of the contract period (00 or 30 minutes) to t-1 minutes. The time used for calculating the integrated energy amount is defined as the integration time.

[0043] The excess determination unit 35 calculates a candidate demand prediction value for each demand period by converting the sum of the predicted power amount and the accumulated power amount into a demand value, and identifies the maximum value among these candidate demand prediction values ​​as the predicted demand value at time t. It then determines whether the identified predicted demand value exceeds the alarm setting value, which is the contracted power, and if it does, it sends a drive signal to the rotating light 6. As a result, the rotating light 6, upon receiving the drive signal, can notify people in the vicinity that the predicted demand value exceeds the contracted power, along with an alarm sound.

[0044] As described above, the integrated energy calculation unit 33 and the predicted energy calculation unit 34 start calculating the candidate demand prediction value from the time period (standard 30-minute demand period) set at time t as the demand monitoring start time, and calculate the candidate demand prediction value for all demand periods while shifting t into the past by one minute at a time, and find the maximum value among the candidate demand prediction values ​​as the predicted demand value at time t. Then, if one minute has passed from the current time t, t = t + 1, and the standard 30-minute demand period is assumed as the new t as the demand monitoring start time.

[0045] This ensures that an alarm can be reliably issued even if there is a time difference between the trading meter 2 and the power monitoring device 10. While the current time t is used as the demand monitoring start time, and the demand forecast value is calculated for each demand time period shifted back one minute at a time, ensuring reliable demand monitoring functionality may increase the frequency of alarms. However, as mentioned above, the frequency of alarms can be appropriately adjusted by setting a calculation exclusion period.

[0046] Next, the operation of the power monitoring device according to this embodiment will be described. Figure 5 is a flowchart showing the operation of the power monitoring device according to this embodiment. The power monitoring device 10 is assumed to be constantly receiving pulse information transmitted from the trading meter 2 via the pulse receiving amplifier 3 by the receiving unit 31 while executing the following series of processes, and storing it in the data storage unit 40. Note that the processes shown in Figure 5 are processes that are executed at fixed intervals of a unit of time (1 minute intervals).

[0047] First, the unit energy calculation unit 32 aggregates the number of pulses for the most recent minute based on the pulse information stored in the data storage unit 40 and calculates the amount of energy used as unit energy (S1). The unit energy calculation unit 32 also configures a standard 30-minute demand time limit that takes into account the calculation exclusion period, and a demand time limit using pulse information up to the past 30 minutes, and sets each demand time limit in the data storage unit 40 (S2). The predicted energy calculation unit 34 calculates the amount of energy used as a predicted energy amount if the unit energy amount calculated in S1 continues until the end of the contract period in the demand time limit being calculated (S3). The cumulative energy calculation unit 33 calculates the amount of energy used from the start time of the contract period in the demand time limit being calculated to time t-1 as the cumulative energy amount (S4). The excess determination unit 35 converts the sum of the predicted power amount calculated in S3 and the cumulative power amount calculated in S4 into a demand value and calculates it as a candidate demand prediction value (S5). Processing from S3 to S5 starts from the standard 30-minute demand period and continues to calculate the candidate demand prediction value until t becomes the contract period.

[0048] The excess determination unit 35 determines whether t at the current demand time is 30 minutes, which is the contract period (S6). If t is not 30 minutes, it adds 1 minute to t (S7) and returns to the process in S3 to calculate the next demand time. If t is 30 minutes in S6, the excess determination unit 35 determines whether the demand prediction value, which is the maximum value of the demand prediction candidate values, is greater than or equal to the alarm setting value, which is the contract power (S8). If the demand prediction value is greater than or equal to the alarm setting value, it sends a drive signal to the rotating light 6 and outputs an alarm (S9), and returns to S1 to prepare for the next 1 minute of processing. If the demand prediction value is less than the alarm setting value in S8, it sends a stop signal to the rotating light 6 and stops the alarm output (S10), and returns to S1 to prepare for the next 1 minute of processing.

[0049] If a calculation exclusion period is set, as described above, the demand prediction candidate values ​​for all time periods will be calculated using multiple demand time periods based on pulse information from the past 30 minutes from the current time t, starting from a standard 30-minute demand time period that takes the calculation exclusion period into consideration. In other words, immediately after the processing of S2, there will be a process (S2' (not shown)) to set t as the demand monitoring start time.

[0050] Furthermore, although the unit time in this embodiment was described as 1 minute, any period may be set. In addition, the length of the unit time may be made variable according to the pulse information. For example, if the number of pulses per unit time acquired by the receiving unit 31 is greater than or equal to a predetermined number, the unit time may be shortened to allow the demand prediction result to be obtained earlier.

[0051] Furthermore, the contract period, start time, and end time can be arbitrarily set. Additionally, the period excluded from calculations can also be arbitrarily set.

[0052] As described above, the power monitoring device 10 according to this embodiment includes: a receiving unit 31 that receives pulse information relating to the amount of power transmitted from the trading meter 2; a unit power amount calculation unit 32 that calculates the amount of power used between the current time and a predetermined unit time before a predetermined unit time as a unit power amount based on the pulse information; a cumulative power amount calculation unit 33 that calculates the amount of power used between the start time of a predetermined contract period and a predetermined unit time as a cumulative power amount based on the pulse information; a predicted power amount calculation unit 34 that calculates the cumulative value of the amount of power if the unit power amount is used continuously until the end time of the contract period as a predicted power amount; and a demand value obtained by converting the total amount of power of the predicted power amount and the cumulative power amount. However, the system includes an excess determination unit 35 that determines whether the contracted power per contracted period is exceeded in advance. The cumulative power calculation unit 33 and the predicted power calculation unit 34 calculate the cumulative power and predicted power for each shifted time period, while shifting the start and end times of the contract period by unit time until the shift amount reaches the size of the contract period. The excess determination unit 35 then determines whether the sum of the predicted power and cumulative power exceeds the contracted power for each shifted time period. Therefore, even if there is a time difference between the trading meter 2 and the power monitoring device 10, demand forecasting can be performed taking that difference into account, thus realizing a monitoring function that does not miss demand oversights.

[0053] Furthermore, the system includes a calculation exclusion period setting means for setting a calculation exclusion period when the cumulative energy calculation unit 33 and the predicted energy calculation unit 34 shift the start and end times of the contract period. The cumulative energy calculation unit 33 and the predicted energy calculation unit 34 do not perform calculations for time periods where the start time is between the current time and the calculation exclusion period. During this time period, there is less pulse information available for demand prediction, which may result in poorer prediction accuracy. Also, during this period, even if the predicted demand value exceeds the demand excess level, there is a considerable margin before it actually exceeds it. Therefore, by not performing demand prediction during this time period, the inconvenience caused by unnecessary alarm output can be eliminated.

[0054] Furthermore, since the unit power calculation unit 32 makes the length of the unit time variable according to the pulse information received by the receiving unit 31, the unit time can be set to an appropriate length, thereby improving the accuracy of demand overload detection.

[0055] (Second embodiment of the present invention) The power monitoring device according to this embodiment will be described with reference to Figures 6 to 8. The power monitoring device 10 according to this embodiment controls the power consumption on the load side in stages according to the predicted demand value. In this embodiment, explanations that overlap with the first embodiment will be omitted.

[0056] Figure 6 is a functional block diagram showing the configuration of the power monitoring device according to this embodiment. The difference between Figure 6 and the configuration in Figure 3 of the first embodiment is the inclusion of a suppression control unit 36 ​​that controls the power consumption on the load side according to the determination result of the overload determination unit 35.

[0057] The suppression control unit 36 ​​performs external control of the air conditioning operation level, for example. Specifically, it has multiple outputs (let's assume three in this case) for power control and sends control contact signals to the air conditioner outdoor unit control box or central remote control. The air conditioner side controls the output based on the control signals transmitted from the suppression control unit 36, thereby controlling the power so as not to exceed the alarm set value.

[0058] The specific control method by the suppression control unit 36 ​​will be described below. Figure 7 is a flowchart showing the processing of the suppression control unit according to this embodiment. In the flowchart of Figure 7, Dt is the predicted demand value at the current time t, and Tt is the cumulative time in the demand time limit used when calculating Dt. In addition, the control level is set to three levels, with control level 3 being a high power suppression level, control level 1 being a low power suppression level, and control level 0 being a state in which the power suppression function is not functioning at all.

[0059] In Figure 7, the suppression control unit 36 ​​determines whether Dt calculated by the excess determination unit 35 is equal to or greater than the alarm set value (S1). If Dt is less than the alarm set value, the current control level is determined (S2). If the current control level is 0, the unit returns to S1 without taking any action. If the current control level is 1, the control level is switched from 1 to 0 (S3). If the current control level is 2, the control level is switched from 2 to 1 (S4). If the current control level is 3, the control level is switched from 3 to 2 (S5), and the unit returns to S1.

[0060] If Dt is above the alarm setting value in S1, it is determined whether Tt is between 28 and 30 (S6). If Tt is between 28 and 30, the control level is increased by three levels (control level 0→3, 1→3, 2→3, 3→3) (S7), and the system returns to S1. In other words, if it is determined that the predicted demand value exceeds the alarm setting value, and the remaining time until the end of the 30-minute contract period in the demand period in which this determination was made is less than 2 minutes, the control level is raised to the maximum because it is necessary to reduce the predicted demand value in a short time.

[0061] If Tt is not between 28 and 30 in S6, it is determined whether Tt is between 25 and 27 (S8). If Tt is between 25 and 27, the control level is increased by two steps (control level 0→2, 1→3, 2→3, 3→3) (S9), and the system returns to S1. In other words, if it is determined that the predicted demand value exceeds the alarm setting value, and there are about 3 to 5 minutes remaining until the end of the 30-minute contract period in the demand time frame in which this determination was made, the control level is increased by two steps because it is necessary to reduce the predicted demand value in a relatively short time.

[0062] If Tt is not between 25 and 27 in S8, the current control level is determined (S10). If the current control level is 3, nothing is done and the system returns to S1. If the current control level is 2, the control level is switched from 2 to 3 (S11). If the current control level is 1, the control level is switched from 1 to 2 (S12). If the current control level is 0, the control level is switched from 0 to 1 (S13) and the system returns to S1. The suppression control unit 36 ​​operates the processes from S1 to S13 in a 1-minute cycle.

[0063] The above process will be explained in more detail with specific examples. Figure 8 is a diagram illustrating an example of the process of the suppression control unit in the power monitoring device according to this embodiment. In the example in Figure 8, the process of the excess determination unit 35 is assumed to be performed every minute. The time axis 81 at the top of Figure 8 represents the passage of time. The YN signal 82 shown directly below it corresponds to the comparison result between Dt and the alarm set value, and is expressed so that the signal becomes Y (ON) when Dt is equal to or greater than the alarm set value. The first control signal 83a shown directly below the YN signal 82 corresponds to the ON / OFF state of control level 1, and is expressed so that it becomes ON when control level 1 is functioning. The second control signal 83b shown directly below the first control signal 83a corresponds to the ON / OFF state of control level 2, and is expressed so that it becomes ON when control level 2 is functioning. The third control signal 83c shown directly below the second control signal 83b corresponds to the ON / OFF state of control level 3, and is expressed so that it becomes ON when control level 3 is functioning. When a Dt that meets the conditions of the cumulative time table 84 shown at the bottom of Figure 8 is selected, and the YN signal 82 becomes Y (ON), the first to third control signals will operate as shown in Figure 8.

[0064] At the timing shown in Figure 8A, when the YN signal 82 turns ON, the first control signal 83a also turns ON. In the next minute, the YN signal 82 turns OFF, so the first control signal 83a also turns OFF. At the timing shown in Figure 8B, when the YN signal 82 turns ON, the first control signal 83a also turns ON. In the next minute, the YN signal 82 remains ON, so the second control signal 83b turns ON. If the YN signal 82 remains ON for the next minute, the third control signal 83c will turn ON. However, in Figure 8, the YN signal 82 is OFF, so the second control signal 83b turns OFF. In the next minute, the YN signal 82 remains OFF, so the first control signal 83a also turns OFF.

[0065] If the cumulative time in the demand time zone adopted as the demand prediction value is between 1 and 24, the control level will move up or down by one step in response to the state change of the YN signal 82.

[0066] At the timing shown in Figure 8C, when the YN signal 82 turns ON, the first control signal 83a also turns ON. Furthermore, since the cumulative time Tt in the demand time used to calculate Dt is within the range of 25 to 27, the control level rises by two steps, and the second control signal 83b also turns ON. In the next minute, the YN signal 82 remains ON, so regardless of the value of Tt, the third control signal 83c turns ON. After that, since the YN signal 82 is OFF, the control level is controlled to decrease in steps every minute.

[0067] At the timing shown in Figure 8, D, when the YN signal 82 turns ON, the first control signal 83a also turns ON. Furthermore, since Tt is within the range of 28 to 30, the control level rises by three steps, and the second control signal 83b and the third control signal 83c also turn ON. In the next minute, the YN signal 82 turns OFF, and in the following minute, the YN signal 82 remains OFF, so the control level gradually decreases, and the third control signal 83c turns OFF sequentially, followed by the second control signal 83b. At this point, in the next minute, the YN signal 82 turns ON again, and since Tt is within the range of 25 to 27, the control level rises by two steps, and the second control signal 83b and the third control signal 83c turn ON. In the following minute, the YN signal 82 remains ON, so the ON state of the third control signal 83c is maintained regardless of the range of Tt. After that, since the YN signal 82 is OFF, the control level is controlled to decrease gradually every minute.

[0068] In other words, the control level is switched according to the continuity of the YN signal 82's state every minute, but especially when Tt exceeds 25 (i.e., when there are less than 5 minutes remaining in the 30-minute contract period), the control level is increased by several steps to prevent the predicted demand value from exceeding the alarm setting value.

[0069] In this embodiment, a configuration for controlling the power reduction of an air conditioner has been described, but it is applicable not only to air conditioners but also to any device that can change its power consumption in response to an external control signal. Furthermore, although a configuration with three control levels has been described, any configuration with multiple levels is acceptable. In addition, in Figure 7, a configuration is shown in which multiple levels of reduction control are performed when the range of Tt is 25 to 30, but the range of Tt may be arbitrarily changed according to the power usage environment, etc.

[0070] Thus, in the power monitoring device according to this embodiment, a suppression control unit 36 ​​is provided that suppresses the power consumption of the load in multiple stages based on the determination result of the excess determination unit 35, so that the demand prediction value does not exceed the alarm setting value.

[0071] Furthermore, if necessary, the suppression control unit 36 ​​will, when the excess determination unit 35 determines that the demand-converted value of the total power amount (predicted power amount + accumulated power amount) exceeds the contracted power, gradually suppress the load according to the remaining time until the end of the contract period at the time the determination was made. This allows for more accurate and reliable control to ensure that the predicted demand value does not exceed the alarm setting value. [Explanation of symbols]

[0072] 1. Power monitoring system 2. Instruments for trading 2a Power pulse CT 3. Pulse receiving amplifier 4. System Management Device 5. Log Management Device 6. Rotating light 7. Sensor Cable 8. Power receiving equipment 9 Amplifier Cables 10 Power monitoring device 10A AC power cord 31 Receiver 32 Unit energy calculation unit 33. Cumulative Power Calculation Unit 34 Predicted Power Calculation Unit 35 Excess judgment section 36 Suppression Control Unit 40 Data storage unit 81 Timeline 82 YN signal 83a First control signal 83b Second control signal 83c Third Control Signal

Claims

1. A receiving unit that receives pulse information regarding the amount of power transmitted from a power meter, A unit energy calculation unit calculates the amount of energy used between the current time and a predetermined unit time before a given unit time based on the pulse information, A cumulative energy calculation unit calculates the amount of energy used between the start time of a predetermined contract period and the unit time based on the pulse information, and A predicted energy consumption calculation unit calculates the cumulative amount of energy consumed when the aforementioned unit energy consumption is used continuously until the end of the contract period, as the predicted energy consumption. The system includes an excess determination unit that determines whether the demand-converted value of the total amount of electricity, which is the sum of the predicted amount of electricity and the accumulated amount of electricity, exceeds the contracted power for the contract period that has been pre-contracted. A power monitoring device characterized in that the cumulative power amount calculation unit and the predicted power amount calculation unit calculate the cumulative power amount and the predicted power amount for each shifted time period while shifting the start time and end time of the contract period by the unit time until the shift amount is equal to the contract period, and the excess determination unit determines whether the demand-converted value of the total power amount of the predicted power amount and the cumulative power amount exceeds the contract power for each shifted time period.

2. In the power monitoring device according to claim 1, When the cumulative energy calculation unit and the predicted energy calculation unit shift the start and end times of the contract period, the system includes a calculation exclusion period setting means for setting a calculation exclusion period during which calculations are excluded. The power monitoring device is characterized in that the cumulative power amount calculation unit and the predicted power amount calculation unit do not perform calculations for time periods whose start time is between the current time and the calculation exclusion period.

3. In the power monitoring device according to claim 1 or 2, A power monitoring device characterized in that the unit power calculation unit makes the length of the unit time variable according to the pulse information received by the receiving unit.

4. In the power monitoring device according to claim 1 or 2, A power monitoring device characterized by comprising a suppression control unit that suppresses the power consumption of a load in multiple stages based on the determination result of the excess determination unit.

5. In the power monitoring device according to claim 4, The suppression control unit, A power monitoring device characterized in that, when the excess determination unit determines that the demand-converted value of the total amount of power, which is the sum of the predicted power amount and the accumulated power amount, exceeds the contracted power, it gradually reduces the load according to the remaining time until the end of the contract period in the time period in which the determination was made.

6. A receiving unit that receives pulse information regarding the amount of power transmitted from a power meter. A unit energy calculation unit calculates the amount of energy used between the current time and a predetermined unit time before a given unit time based on the pulse information. A cumulative energy calculation unit calculates the amount of energy used between the start time of a predetermined contract period and the unit time based on the pulse information, as the cumulative energy amount. A predicted energy calculation unit calculates the cumulative amount of energy used if the aforementioned unit energy is used continuously until the end of the contract period, and this cumulative amount is used as the predicted energy amount. The computer functions as an excess determination unit to determine whether the demand-converted value of the total amount of electricity, which is the sum of the predicted amount of electricity and the accumulated amount of electricity, exceeds the contracted power for the contract period that has been agreed upon in advance. A power monitoring program characterized in that the cumulative power amount calculation unit and the predicted power amount calculation unit calculate the cumulative power amount and the predicted power amount for each shifted time period while shifting the start time and end time of the contract period by the unit time until the shift amount is equal to the contract period, and the excess determination unit determines whether the demand-converted value of the total power amount of the predicted power amount and the cumulative power amount exceeds the contract power for each shifted time period.

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