JP2701360B2 - Integrated power meter - Google Patents

Description

The present invention relates to an integrated wattmeter, and more particularly to an integrated wattmeter in which the power consumption is displayed numerically.

(B) Conventional technology In general, a moving magnetic field-type inductive integrating wattmeter is used for measuring the amount of electric power of a commercial frequency used in an office or at home. In this type of integrated wattmeter, the amount of power used is displayed by mechanically indicating the number of rotations of an aluminum disk obtained according to the use of electric power, or by using a mechanical digital display. .

(C) Problems to be Solved by the Invention In recent years, energy saving has been called for in terms of effective use of limited resources and economical use of resources. Electricity energy is no exception, and business establishments and homes are also demanding efficient use of electric power without waste.
Therefore, at each business establishment and each household, from the perspective of reflecting on power consumption and making detailed plans for use, and completely executing power use management, it is easy to know not only power consumption but also usage fees. There is a need to get it. However, in the conventional integrated wattmeter, only the power consumption is displayed, and a staff member reads the power consumption, reads the power consumption, and obtains the usage fee by referring to the fee table from the power consumption. It is very difficult and it is very difficult for an amateur who does not have knowledge of meter reading to find a usage fee. In addition, the conventional integrating wattmeter is of a fixed type and is usually provided for one power supply in one system. Therefore, not only can the portable power meter be freely carried, but also in business establishments and the like having several power supply systems. In addition, an integrating wattmeter had to be installed for each system.

Also, in the integrating wattmeter, when the current signal of the power line to be measured is taken and the electric energy is calculated based on the current signal, even if the same current signal is taken, the current specification of the current transformer to be used and the system under test Depends on the voltage, the number of phases, and the like. Therefore, when the current specification of the current transformer, the voltage of the system to be measured, and the number of phases are fixed by the electric energy calculation means, the integrated wattmeter can be used only for the system to be measured of the fixed standard. There is.

The present invention has been made in view of the above-mentioned problems, and is portable, can be set anywhere, and can detect the integrated power amount and usage fee of a plurality of systems by one. It aims to provide a wattmeter.

It is another object of the present invention to provide an integrating wattmeter that can be used for various systems under measurement and current transformer standards.

(D) Means and Action for Solving the Problems The integrating wattmeter according to the present invention has a current transformer coupled to a power line to be measured and detecting a current, and an amplifying current signal detected by the current transformer. A plurality of current signal capturing units, each of which includes a signal conversion circuit that converts the DC signal into a DC signal,
A plurality of setting means for individually switching and setting in accordance with the specifications of the current transformer and the characteristics of the load; current signals taken from respective current signal capturing units; each specification of the current transformer; and characteristics of the load A power amount calculating means for calculating the power amount of each system based on the data determined by the above, an integrated power amount calculating means for integrating the calculated power amounts of the plurality of systems, and performing a predetermined operation on the integrated power amount, The system includes a usage fee calculation unit for calculating the usage fee of the integrated power amount, and a display unit for digitally displaying the integrated power amount and the usage fee (see FIG. 1).

In this integrating wattmeter, for example, the voltage and the number of phases of a plurality of systems to be measured and the current specification of a current transformer to be used are selected and set in advance by each setting means (example: 100 V, single phase, 20 A). When the current transformers of the current signal acquisition units of the respective systems are respectively coupled to the power lines of the measured power system, currents corresponding to the powers of the corresponding measured power systems flow through the respective current transformers. Then, these current signals are amplified by respective signal conversion circuits and converted to direct current, and are converted into data according to the specification of the voltage, the number of phases, and the current transformer set by the setting means to the current signals by the respective electric energy calculation means. Based on this, the electric energy for each system is calculated. Then, these calculated power amounts are integrated by the integrated power amount calculation means over time. In addition, the usage fee calculation means multiplies the integrated electric energy by, for example, a unit fee set in advance, and calculates the usage fee. Then, the calculated integrated power amount and usage fee are digitally displayed on the display means. This integrated wattmeter displays the total integrated power amount of the power system to which each current transformer is coupled and the usage fee.

(E) Examples Hereinafter, the present invention will be described in more detail with reference to examples.

FIG. 2 is a circuit diagram of an integrating wattmeter showing one embodiment of the present invention. This integrating wattmeter includes a CPU 1, a clock oscillator 2 for generating a synchronization signal, a current transformer CT ₁ (CT ₂ ) externally connected to terminals P _1a and P _2a (P _1b and P _2b ), and (See Figure 3),
The current detected by the current transformer CT ₁ (CT ₂ ) is converted into a signal
, A signal display circuit (LED) 4 for displaying a 4-digit numerical value, a digit driving circuit 6 for driving the display 4 digitly, a segment decoder 7, a terminal P ₃ , with a commercial voltage of 100V to P _4, each circuit + 12V, -12V, and the power supply circuit 7 for supplying a power supply voltage such as + 5V, the supply voltage drop detection circuit 8 for detecting a supply voltage drop, the memory in the CPU 1 (RA
M) backup circuit 9 and indicator light L
_1, L _2, ..., and L _4, various settings switch _{SW 1, SW 2, ...,} SW
_{Consists of 12} parts.

Signal conversion circuit 3a includes an absolute value rectifier circuit including the operational amplifier AM _1, AM _2, terminal P _1a, amplifies a signal corresponding to the detected current input through P _2a, full-wave rectification, and smoothing It has the function to do. Also, the operational amplifier
At the subsequent stage of AM ₂ , a smoothing circuit including a delay function for further smoothing the rectified and smoothed current signal and for suppressing a sudden change is provided. The signal conversion circuit 3a, the current I corresponding to the current flowing in the measuring circuit is detected by the current transformer CT ₁ is converted to a direct current component, CPU 1
Is input to

The example energy meter, as electric energy of two systems can be measured, current transformer CT _1, in addition to current transformer C of the signal conversion circuit 3a
At T ₂ , the signal conversion circuit 3b is juxtaposed. Signal conversion circuit 3b
Is a circuit having the same configuration and function as the signal conversion circuit 3a.

The switches SW ₁ , SW ₂ ,…, SW ₁₀ are all dip switches. Of these switches, the switches SW ₁ , SW ₂ , SW ₃ are setting switches for the current transformer CT ₁ , and the load (measured system) This is for setting the power supply voltage to 100V / 200V, single-phase / three-phase, and the current transformer rated 20A / 100A. Similarly, the switches SW ₄ , SW ₅ , and SW ₆ are setting switches for the current transformer CT ₂ , and are respectively 100 V / 200 V, single-phase /
It is for setting different of three phase, 20A / 100A. The switches SW ₇ , SW ₈ , and SW ₉ are for adding and setting the unit price. The unit price is a base unit price of 18 yen, which is registered and stored in the CPU 1 in advance. Set with switches SW ₇ , SW ₈ and SW ₉ . +1 yen, +
Set 2 yen and +4 yen. Therefore, in the integrated power meter of this embodiment, a unit price of 18 yen to 25 yen can be set. Switch SW ₁₀ is used to set the two-phase detection mode in three phases. Switch SW ₁₁ is for resetting, also switch SW ₁₂ is a switch of the display switching.

The ON / OFF states of the switches SW ₁ , SW ₂ ,..., SW ₁₂ are taken into the CPU 1.

The CPU 1 has an A / D conversion function, a function of converting the current signal I into a digital signal from the two-series signal conversion circuits 3a and 3b and taking in the digital signal, and the switches SW ₁ ,... SW ₃ and SW ₄ ,. _It has a function of reading out reference data determined by the setting conditions of ₆ from the built-in ROM and multiplying the current signal I to calculate the amount of power. Here, the reference data is the amount of power output when a current signal corresponding to one bit is input from the A / D converter. The reference data is 100 V / 200 V, single-phase / three-phase, 2
Eight types for 0A / 100A are stored. Now, for example, A / D converter is a 256-bit, relates current transformer CT _1, setting is 200V, three phase, when 20A, reference data D
Is However, the power factor is fixed at 0.85. Further, for example, if the setting is 100 V, single phase, 20 A, the reference data D is Becomes

CPU1 further function of calculating the integral power consumption by integrating the amount of power, the ability to calculate the rates used by multiplying the set to the integrated amount of power calculated unit price, depending on the ON / OFF setting status of the switch SW ₁₂ And a function of switching and displaying the integrated output amount and the usage fee on the display 4.

Indicator light L ₁ is lit when the display is switched in the room rate. This indicator light has a weight of one hundred yen. Therefore, indicator lamp L ₁ is lit and the display of the display device 4 is 52, charge for approximation is 5 2,200 yen. Indicator L ₂ is lit when the display is switched to the integral power consumption. The indicator lamps L ₃ and L ₄ have current transformers CT ₁ and CT _{2 with} a specification of 100A, and the switch SW
_3. Lights when SW ₆ is turned on.

FIG. 4 is an external plan view of the integrating wattmeter of the embodiment. In the figure, on the upper surface of the main body case 20, a display unit 4, a display lamp L _1, L _2, a reset button SW _11a, but the display switching button SW _12a it is visibly arranged, shown in Figure 2 The other circuit units are housed in the main body case 20. More buttons SW _11a and SW _12a are covered by the transparent cover 20a of the body case 20, and the reset button SW
_11a can not be operated without removing the body case 20a,
The display switching button SW _12a cannot be turned ON / OFF unless a bar or the like is inserted from the small hole 20b and operated, thereby preventing erroneous setting due to easy hand touch.

When using the integrated power meter of this embodiment, the terminals P _1a and P _2a
To the current transformer CT ₁ connected, terminals P _1b, insertion and binds to a single load power line to be measured the current transformer CT ₂ connected to P _2b, respectively (e.g., see FIG. 3). Then, the setting of each of the current transformers CT ₁ and CT ₂ is set by the switch S.
W _1, ..., carried out in SW _6. In this case, the current transformer CT ₁ and the current transformer CT ₂
The settings for the two current transformers may be made independently and when the power system is different, the settings may be different for both current transformers.

Therefore, relates current transformer CT _1, the switch SW ₁ is set to 100V side, this setting of the switch SW ₄ according to the current transformer CT ₂ to is also possible when set to 200V, also, the switch
While setting by SW ₂ is a three-phase, set by the switch SW ₅ is no problem even if an equal a single phase. However, this is the case where both current transformers CT ₁ and CT ₂ are coupled to one of the same three-phase load power lines, respectively. A current signal corresponding to the power amount is detected by each series, and based on this, a current signal can be obtained. and if the average amount of power, in the case of the two-phase detection that is in the three-phase when the switch SW ₁₀ is oN, current transformer
It is necessary that CT ₁ and CT ₂ have the same condition setting.

The switches SW ₇ ,..., SW ₉ set an additional charge for 18 yen. If the unit price is 18 yen, which is equivalent to the base charge, all of the switches SW ₇ ,..., SW ₉ may be turned off. On the other hand, if the unit price is set to 25 yen, the switches SW ₇ , SW ₈ and SW ₉ are both turned on.

Next, the overall operation of the integrating wattmeter of the embodiment will be described with reference to the flowchart shown in FIG.

When the power is turned on and the operation starts, the CPU 1 first performs the initial processing of the system [Step ST (hereinafter referred to as ST).
Next, it is determined whether or not a counter reset is requested (ST2). Here counter reset request and the count value that counts the integrated electricity a request to 0, ON the switch SW ₁₁ is performed, this reset request flag is set by the key interrupt by. When the reset request flag is ON, the determination as to whether or not the counter is a reset request is YES. If the determination in ST2 is YES, then
The reset request flag is cleared (ST3) and counter reset processing is performed, that is, the content of the counter is set to 0 (ST3).
4) The contents of the counter are subjected to BCD conversion processing (ST5), and a display stack operation is performed (ST6). Here, the contents of the counter are output to the display 4 via the segment decoder 6 by the display stack operation, and are displayed as they are. Therefore, the display of the reset state is
Since the integrated power amount and the usage fee up to that point are all set to 0, 0 is displayed. Then move to ST7. On the other hand, when the reset request flag is 0 in ST2, the determination is NO, and the process jumps to ST7 to determine whether there is a display switching request. Here, the display switching request means the switch SW
_{When the} switch ₁₂ is turned on, a switch request flag is set by an interrupt from the switch operation.
When the SW ₁₂ is operated, the switching request flag is ON, and in this case, the determination is YES. If there is a switching request, in a state in which clear the switching request flag ST8, originally indicator L ₂ showing the black watt-hours is lit, when the switch SW ₁₂ is turned ON, the indicator L ₁ Performs LED display processing to turn on (ST9), and calculates the charge B calculated by the charge counter.
The CD conversion process is performed (ST10), and the converted usage fee data is displayed and operated (ST11), and the usage fee is displayed on the display unit 4 in hundred yen units. In ST7, if at the stage before the display switching, which indicator lamp L ₁ is turned, that is displayed is the use fee displayed indicator in the LED display processing ST9
Switching the lighting of L _2, carried out in the same manner as in ST10, BCD conversion and display stack operation in ST11, thereby displaying a use integrated electricity on the display unit 4.

Next, the process proceeds to ST12 to determine whether or not there is an execution request. The execution request is generated by a separately provided time interruption every second. The condition of the execution request becomes YES every second, and the process shifts from ST12 to ST13 to set the output during execution. This output set during execution is set for testing. Then, in ST14, performs A / D conversion processing, respectively, the signal conversion circuit 3a, takes in the current input to be detected from the current transformer CT ₁ and CT ₂ is taken from 3b, stores, followed by ST15 It is determined whether or not to stop the power integration (ST15). This power integration stop is to detect this and display an error before the integrated power amount counter counts up. If the power integration is stopped, the process proceeds to ST28 described later. If the power integration is not stopped, the input of each dip switch is taken in (ST16). Here, the dip switch input is the setting condition of each of the current transformers CT ₁ and CT ₂ from the switch SW ₁ to the switch SW ₆ , the added value of the fee of the switches SW ₇ ,..., SW ₉ , and the switch SW
₁₀ ON / OFF signals for three-phase two-wire processing. Then 3 phase 2
It is determined whether or not there is a line setting error (ST17). In the case of a three-phase two-line setting error, the process also jumps to ST28. Determining conditions 3-phase two-wire setting errors, three-phase two-wire detection switch SW ₁₀ is a case where ON / OFF of the switch SW _3, SW ₆ do not match. If it is not a three-phase two-wire setting error, it is next determined whether or not a three-phase two-wire detection is performed (ST18). Here, 3-phase two-wire detection is a judgment as to whether the switch SW ₁₀ is ON, the switch
If the SW ₁₀ is not ON, a process of detecting the power of the normal two series, therefore, first, the current transformer CT ₁ performs calculation set (ST19), the signal conversion circuit 3a, the input terminal AN ₀ Multiply the current value taken through by the reference data corresponding to each set condition, and the current transformer CT ₁ at this time.
(ST20). Then, after the reset, the power amount calculated this time is added to the integrated power amount stored in the counter of the RAM until then (ST21). Then, in turn, performs the calculations set for a current transformer ST ₂ (ST22). Similarly, the power calculation of the power system to which the current transformer CT ₂ is coupled is performed, and the current transformers CT ₁ and C
Integrates the integrated electricity of the power system according to this CT ₂ to integrated electricity about T _1, calculates the integrated electricity of total total 2 series (ST24). The total integrated power amount is multiplied by the set unit price to calculate a usage fee (ST25). This usage fee is of course also stored in the RAM in the CPU1. Subsequently, it is determined whether or not the usage fee exceeds one million yen (ST26). If the usage fee exceeds one million yen, the process jumps to ST28. If the amount does not exceed one million yen, after performing the BCD conversion processing (ST27), the display stack operation is performed, and the usage fee or the electric energy is displayed on the display 4 according to the switching condition (ST28). In this case, the LED display process is performed similarly (ST29). LED display process, when the display of the power rate is to light the indicator lamp L _1, if the integrated amount of power to light the indicator lamp L _2, is similar to that described above. Note that in ST28, when an error occurs, such as when the display is not a normal display, that is, when the integrated power value is stopped, or when the determination is YES when the determination is over one million yen,
Flashing and lighting indicating each of them or display in a special mode is performed. When the LED display process of ST21 is completed, the execution request flag that has been ON until that time is cleared (ST3
0), backup decision data is set (ST31).
Here, the backup determination data is data set in the RAM of the CPU for making a backup determination, and is used to check whether backup is sufficient in another routine. After that, the output during execution is reset (ST32), and the process returns to ST2. Thereafter, the same process is sequentially repeated. The processing of ST7 to ST11 is performed, and further, if there is an execution request every 1 second, the processing of ST12 to ST32 is repeated, and the power calculation of each power system is performed every 1 second, The power amount calculated this time is added to the integrated power amount up to that time, a charge calculation is performed on the total power amount, and the operation is continued.

In the above-described embodiment, two current signal capturing units each including a current transformer and a signal conversion circuit are provided.
The present invention is not limited to this, and one or three or more lines may be provided.

The switches SW ₁ to SW ₆ for setting, for each current transformer, but are set two kinds of conditions, the more the required ones, there is for selecting and setting three or more conditions Is also good.

Further, in the above embodiment, the captured current signal
Although the reference data to be multiplied is read from the ROM according to the combination of the setting conditions, the power may be calculated by calculating the set value and the current signal corresponding to the setting switch each time.

Further, in the above-described embodiment, the usage charge is calculated by multiplying the integrated power amount by the set unit price.
May be registered in the storage device and selectively read out.

Further, in the above embodiment, the integrated power amount and the usage fee are switched and displayed on the display 4, but these may be displayed in parallel with individual displays, or Further, the power amount may be switched and displayed in addition to the integrated power amount and the usage fee.

(F) Effect of the Invention According to the present invention, it is possible to obtain an integrated power meter that is very small and compact and can be carried anywhere. Further, it is only necessary to couple the non-measurement power line to the current transformer, so that installation is also possible. It is easy and, besides, the usage fee is displayed in addition to the accumulated power, so you do not need special knowledge of meter reading, etc.
Anyone can use it easily, and can immediately know the usage fee as needed, so that an integrated power meter that is extremely convenient for power management can be obtained.

In addition, since a plurality of current signal capturing units are provided, it is possible to know the integrated power amount and the usage fee of the power system of different systems by one unit.

Also, for example, since there are provided setting means for individually switching and setting the specification of the current transformer, the number of phases of the non-measurement system, and the voltage, an appropriate power amount calculation is performed according to the non-measurement system, that is, the load state. Therefore, it is possible to obtain a highly versatile integrated wattmeter that can be used in various non-measurement systems.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a circuit diagram of an integrating wattmeter showing one embodiment of the present invention, and FIG. 3 is a transformer connected to a terminal of the integrating wattmeter. FIG. 4 is a circuit diagram showing a flow distributor, FIG. 4 is a plan view of the external appearance of the integrating wattmeter of the embodiment, and FIG. 5 is a flowchart for explaining the operation of the integrating wattmeter. 1: CPU, 3a · 3b: signal conversion circuit, 4: display, CT ₁ · CT _2: current _{transformer, SW 1, SW 2, ...} , SW 6: setting switch regarding the measurement system.

Claims (1)

(57) [Claims] A plurality of systems each comprising a current transformer coupled to a power line to be measured and detecting a current, and a signal conversion circuit for amplifying a current signal detected by the current transformer and converting the signal into a DC signal. A current signal capturing unit, a plurality of setting means for individually switching and setting each of the current transformers according to the specifications of the current transformers and the characteristics of the load, and a current captured from each current signal capturing unit. A power amount calculating means for calculating the power amount of each system based on a signal, data of each specification of the current transformer, and characteristics of a load; an integrated power amount calculating means for integrating the calculated power amounts of the plurality of systems And a predetermined calculation is performed on the integrated power amount to calculate a usage fee for the integrated power amount, and display means for digitally displaying the integrated power amount and the usage fee. Power meter.