JPH0266463A - Integrating wattmeter - Google Patents

Abstract

PURPOSE:To constitute an integrating wattmeter as a portable type to be optionally carried and to simply detect a using rate by detecting the current of a power line to be measured, integrating calculated electric energy and executing the prescribed operation of the integrated electric energy to calculate the using rate. CONSTITUTION:When a power source is turned on and operation is started, a CPU 1 turns on a switch SW11 and sets up a reset request flag. Then, the CPU 1 sets up the contents of an integrated electric energy counter to '0' and executes display stack operation. The contents of the counter are outputted to a display device by the display stack operation through a segment decoder 6 and '0' is displayed. When a switching request is generated, LED display processing for turning on a display lamp L1 when a switch SW12 is turned on in the ON state of a display lamp L2 kilowatt hour is executed, the BCD conversion processing of a rate calculated by a rate counter is executed and the display stack operation of the converted using rate data is executed to display the using rate on the display device 4 in each 100 yen.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an integrating wattmeter, and particularly to an integrating wattmeter that numerically displays the power consumption rate.

(B) Conventional Technology In general, a moving magnetic field type inductive integrating wattmeter is used to measure the amount of power at commercial frequencies used in businesses and homes. In this type of integrated wattmeter, the amount of power used is displayed by a mechanical needle indicating the number of rotations of an aluminum disc that is obtained according to the amount of power used, or by a mechanical digital display. Ta.

(c) Problems to be solved by the invention In recent years, there has been a call for energy conservation in terms of the effective use of limited resources and the economical use of resources.

Electric energy is no exception, and businesses and households are required to eliminate wasteful use of electricity and use it efficiently. Therefore, each business office and each household should reflect on their electricity usage, formulate a detailed usage plan, and fully manage electricity usage by easily knowing not only the amount of electricity used but also the usage charges. There is a growing need to obtain it. However, conventional integrated power meters simply display the amount of power used, and the staff reads the meter each time, reads the amount of power used, and calculates the usage fee by referring to the rate table based on the amount of power used. In addition to being time-consuming, it was extremely difficult for amateurs with no knowledge of meter reading to obtain usage fees. In addition, because conventional integrating power meters are fixed-mounted, they are inconvenient to carry and cannot be carried freely and measured anywhere, which also limits their use. there were.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an integrated wattmeter that can be configured to be portable and can easily be used to detect usage charges.

(d) Means and Effects for Solving the Problems The integrating wattmeter of the present invention includes a current transformer that is coupled to a power line to be measured and detects current, and amplifies the current signal detected by the current transformer. and a signal conversion circuit that converts it into a DC signal, a power amount calculation means that calculates power based on the current signal from this signal conversion circuit, an integrated power amount calculation means that integrates the calculated power amount, and this integrated power amount. It is comprised of a usage fee calculation means that performs a predetermined calculation on the amount of electricity and calculates the usage fee for the integrated power amount, and a display means that digitally displays the integrated amount of power and the usage fee (see FIG. 1).

In this integrating wattmeter, when a current transformer is connected to the power line under test, a current flows through the current transformer according to the load power, and this current signal is amplified and converted to direct current in a signal conversion circuit to calculate power. The means multiplies the current signal by setting data such as a set voltage, and calculates the electric energy. Then, as time passes, this power amount is integrated by the integrated power calculation means, and the integrated power amount for a predetermined period is calculated. Further, the usage fee calculation means multiplies the integrated power amount by, for example, a preset unit fee to calculate the usage fee.

Then, the calculated integrated power amount and usage fee are digitally displayed on the display means.

(E) Examples The present invention will be explained in more detail with reference to Examples below.

FIG. 2 is a circuit diagram of an integrating power meter showing an embodiment of the present invention. This integrated power meter includes a CPUI, a clock oscillator 2 for generating a synchronization signal, and terminals P Ia and P
Current transformer CT+ (CTz) (see Figure 3), which is externally connected to z-(P, b, Pzb), and current transformer C
A signal conversion circuit 3a (3b) that converts the current detected by T l (Cr t ) into a signal and inputs it to the CPUI, an indicator (LED) 4 that displays a 4-digit numerical value, and this indicator 4.
The finger drive circuit 6 that drives the finger, the segment decoder 7, and the terminals Pi and P receive a commercial voltage of 100V, and each circuit has +12V and -12V.

A power supply circuit 7 that supplies a power supply voltage such as +5V, a power supply voltage drop detection circuit 8 that detects a drop in power supply voltage, and a CPUI.
It consists of a backup circuit 9 for backing up the internal memory (RAM), indicator lights , L, . . . , L4, and various setting switches sw, , sw, . . . , 5W12.

The signal conversion circuit 3a includes an absolute value rectifier circuit composed of operational amplifiers AM, AMg, and terminals P Ill, PLa.
It has the functions of amplifying, full-wave rectifying, and smoothing the signal corresponding to the detected current input through the sensor.

Furthermore, a smoothing circuit that further smoothes the rectified and smoothed current signal and includes a delay function that suppresses sudden changes is provided at a subsequent stage of the operational amplifier AM. The signal conversion circuit 3a converts the current (2) corresponding to the current flowing through the system under test detected by the current transformer CT into a DC component and inputs it to the CPUI. In the integrated power meter of this embodiment, in addition to the current transformer CTr and the signal conversion circuit 3a, a current transformer CT2 and a signal conversion circuit 3b are arranged in parallel so that the electric energy of two systems can be measured. The signal conversion circuit 3b is a circuit having the same configuration and function as the signal conversion circuit 3a.

Switches S W+ , S Wz , ..., SWl. Dip switches are used in all of these, and among these, switches SWI, swt, and SW are setting switches for the current transformer CT, and are set to 100V/200V of the load power supply voltage.
, single phase/three phase, and current transformer rating 20A/10
This is for setting 0A. Similarly, the switches SW, SWs, SWb are setting switches for the current transformer CT, and each has a voltage of 100 V/200
This is for setting V, single phase/three phase, and 20A/100A. Switches SW1, SW8, and SW are used to add and set the unit price. Regarding the unit price, the standard unit price of 18 yen is registered in advance in the CPUI, and the yen to be added and corrected is The switch SW7,
Set with sw8, sw. +1 yen, +2 yen, respectively.
Set +4 yen. Therefore, in this example integrated wattmeter, a unit price of 18 yen to 25 yen can be set. The switch SW1° is for setting a two-phase detection mode in three phases. The switches SW, 2 are for resetting, and the switches SW, 2 are for changing the display.

Switch SW+, SWz,..., SW, □
The ON/○FF state of is taken into the CPUI.

The CPU has an A/D conversion function, a function of converting the current signal ■ into a digital signal from the two signal conversion circuits 3a and 3b, and taking in the digital signal, and switches SW, ~SW3 and S.
It has a function of reading reference data determined by the setting conditions of W, ~SW, from the built-in ROM and multiplying it by the current signal (2) to calculate the amount of electric power. Here, the reference data is A/
This is the amount of power output when a current signal equivalent to 1 bit is input from the D converter, and the reference data is 100
Eight types are stored, including V/200V, single phase/three phase, and 2OA/100A. For example, if the A/D converter is 256 bits, and the current transformer CT is set to 200V, three-phase, and 20A, then the reference data D is such that the power factor is fixed at 0.85.

The CPU also has a function that calculates the cumulative power amount by further integrating the power amount, a function that calculates the usage fee by multiplying the calculated cumulative power amount by the set unit price, and a function that calculates the usage fee by turning on switch SW1□.
10 FF It has a function of switching and displaying the integrated power amount and usage fee on the display 4 according to the setting status of the FF.

The indicator light L1 lights up when the display is switched to fare. This indicator light has a weight of 100 yen. Therefore, if the indicator light L1 is lit and the display on the display 4 is 52, the estimated usage fee is 5,200 yen. The indicator light L2 lights up when the display is switched to the integrated power amount. Indicator light 3,
For L4, the specifications of current transformers CT + and CT z are 1, respectively.
0OA, and lights up when switches SW3 and SW6 are turned on.

FIG. 4 is an external plan view of the integrated power meter of the above embodiment.

In the figure, a display 4,
The indicator lights Lt, Lz, reset button SW, ..., display switching button SW1□ are arranged so as to be visible, but the other circuit parts shown in FIG. 2 are housed inside the main body case 20. . Most button: / S W + + a
, SW, ... are covered by the transparent cover 20a of the main body case 2o, the reset button SW, ... cannot be operated unless the main body case 20a is removed, and the display switching button SW, 2° is hidden from the small hole 20b. 0N10FF cannot be performed unless a bar etc. is inserted and operated.
This prevents incorrect settings caused by simply touching the nodes.

When using this embodiment of the integrated power meter, terminals P, Pt
a current transformer CTl connected to m, and a terminal P rbs P
Each current transformer CT2 connected to Zb is inserted and coupled to one of the load power lines to be measured. Then, the respective settings regarding the current transformers CT, . . . , C70 are performed using the switches SW, . in this case,
Settings regarding the current transformers CTl and current transformer CT2 are performed individually and independently, and when the power systems are different, different settings may be made for both current transformers.

Therefore, for current transformer CT, switch SW is 1
It is also possible to set the switch SW4 by the current transformer CT2 to 00■ side, and set the switch SW4 by the current transformer CT2 to 200■.Also, while the setting by the switch SW2 is three-phase, the setting by the switch SW There is no problem even if the setting is single phase. However, the double flow device CT, ,C70
This is a case where the switch S In the case of two-phase detection in three phases when W, , is ON, current transformers CT, ,C
T, is required to have the same condition setting.

After coupling the current transformers CT, . . . , CT2 to their respective intended load power lines, corresponding settings of the respective current transformers CT, .

Also, of course, switches SW7,..., SW.

Set the additional charge for 18 yen. If the unit price is 18 yen, which corresponds to the standard charge, switch SW1, SW8
, SW, should be turned OFF.On the other hand, if you want to set the unit price to 25 yen, switch SW7,
Both SW8 and SW will be turned on.

Next, the overall operation of the integrated power meter of the above embodiment will be explained according to the flowchart shown in FIG.

When the power is turned on and operation starts, CPU1
First, initial processing of the system is performed [step ST (
(hereinafter referred to as ST)1). Next, it is determined whether a counter reset is requested (Sr1).

Here, the counter reset request is a request to set the count value for counting the integrated power amount to O, and
, is turned ON, and a reset request flag is set by the key interrupt caused by this.

When this reset request flag is ON, the determination as to whether it is a counter reset request becomes YES. Judgment of Sr1 is Y
If it is ES, then the reset request flag is cleared (Sr1), the counter is reset, that is, the contents of the counter are set to O (5T4), the contents of the counter are converted to BCD (5T5), and the display stack is The operation is performed (S76). Here, by display stack operation, the contents of the counter are transferred to the display 4 via the segment recorder 6.
will be output and displayed as is.

Therefore, when the reset is performed, the accumulated power amount and usage charges up to that point are all set to 0.
O will be displayed. After that, the process moves to ST7. On the other hand, if the reset request flag is 0 in Sr1, this determination becomes No, and the process jumps to Sr1 to determine whether there is a display switching request.

Here, the display switching request means that when the switch SW1□ is turned ON, a switching request flag is set due to an interrupt caused by the switch operation, and when the switch SW1□ is operated, the switching request flag is set ON. has been
In this case, the determination is YES. When there is a switching request, the switching request flag is cleared with Sr1, and when switch SW1□ is turned on while indicator light L2 indicating kilowatt hours is initially lit, the indicator light is turned on. A lighting LED display process is performed (Sr1). Performs BCD conversion processing of the charge calculated by the charge counter (STIO
). This converted usage fee data is subjected to a display stack operation (STII), and the usage fee is displayed on the display 4 in units of 100 yen. In Sr1, before switching the display, if the indicator light L2 is lit, that is, if the display is the usage fee display, the LED display process in Sr1 switches the indicator light L2 to light, and similarly, 5TIO, 5TII BCD conversion processing and display stack operation are performed, and the integrated power consumption is displayed on the display 4.

Next, the process moves to 5T12, and it is determined whether or not it is an execution request. This execution request is generated by a time interrupt provided separately every second, and when the condition for an execution request every second becomes YES, the process moves from 5TI2 to 5T13, and the output during execution is sent.

This running output set is set for testing. Subsequently, A/D conversion processing is performed at 5T14.

The current inputs detected by the current transformers CT and CTz taken in from the signal conversion circuits 3a and 3b, respectively, are taken in and stored, and then it is determined at 5T15 whether or not the power integration is stopped (ST15). . This power integration stop is detected before the integrated power amount counter counts up, and an error is displayed. If the power integration is to be stopped, the process moves to step 5T28, which will be described later, but if the power integration is not to be stopped, the inputs from each dip switch are taken in (ST16). Here, the dip switch inputs are the setting conditions of each current transformer CT+, CT from switch SWl to switch SW6, and the settings for switches SW7 to SW7.

, and the ON10 FF signal of the 3-phase 2-wire processing of switches SW and o. Next, it is determined whether or not there is a three-phase two-wire setting error (5T17), and if there is a three-phase two-wire setting error, the process also jumps to 5T28. The conditions for determining a 3-phase 2-wire setting error are: 3-phase 2-wire detection switch SW, 0
is ON, switches SW3 and SW6 are ON10 F F
This is the case when # matches.

If there is no three-phase, two-wire setting error, then it is determined whether or not three-phase, two-wire detection has occurred (ST18). Here, 3-phase 2-wire detection is performed by switch SW. This is a determination as to whether or not the switch SW is turned on. is not turned on,
This is a normal two-series power amount detection process, and therefore,
First, a calculation set is performed for the current transformer CT (STI9
). The signal conversion circuit 3a multiplies the current value taken in through the input terminal ANO by reference data corresponding to each setting condition, and calculates the power of the power system to which the current transformer CT is connected at this point (ST20). . Then, after the reset, the currently calculated power amount is integrated into the cumulative power amount stored in the RAM0 counter until then (ST2
1). Next, a calculation set regarding the current transformer CT2 is performed (ST22). Similarly, calculate the power of the power system to which the current transformer CT is connected, and calculate the power of the current transformer OCT.
, and C.T.

The integrated power amount of the power system related to the current CT 2 is integrated with the integrated power amount of the current CT 2, and the total integrated power amount of the two systems is calculated (ST24). This total integrated power amount is multiplied by the set unit price charge to calculate the usage charge (ST25
). Of course, this usage fee is also stored in the RAM within the CPUI. Next, it is determined whether the usage fee exceeds one million yen (5T26), and if it exceeds one million yen, it jumps to Sr1 B. If it does not exceed one million yen, it performs BCD conversion processing (ST27). , performs a display stack operation and displays the usage fee or integrated power amount on the display 4 according to the switching conditions (ST28). In this case, the LED
Display processing is also performed (ST29). The LED display process is the same as in the case described above, in which the indicator light L1 is turned on in the case of displaying the power rate, and the indicator light L2 is turned on in the case of the integrated power amount.

In addition, in Sr18, if the display is not normal, that is, if the integrated power value is stopped, the judgment is YES if it is over a million yen.
In the event of an error occurrence, such as in the case of , a blinking light will be displayed to indicate the respective situation, or a special response will be displayed. When the LED display process of Sr11 is completed, clear the execution request flag that was ON until then (5T30)
, set backup judgment data (Sr31),
Here, the backup judgment data is data set in the RAM of the CPU for making a backup judgment, and is used in another routine to check whether the backup is sufficient. After that, the execution output is reset (5T32), the process returns to Sr1, and the same process is repeated sequentially. If there is a request to reset the counter, processes from Sr1 to Sr6 are performed, and if there is a request to switch the display, In this case, the processing of Sr1 to 5TII is performed, and further, in the case of an execution request every 1 second, the processing of 5T12 to Sr32 is repeated, and the power calculation of each power system is performed every 1 second. The current calculated amount of electricity is added to the previous integrated amount of electricity, a fee is calculated for the total amount of electricity, and the operation continues.

Note that in the above embodiment, two series of electric energy intake sections each consisting of a current transformer and a signal conversion circuit are provided, but the present invention is not limited to this;
More than one series may be provided.

In addition, the setting switches SW1 to SW6 each set two types of conditions for the current transformer, but they are fixed to one type, that is, the switches SW1, ..., SW are omitted. Alternatively, three or more types of conditions may be selected and set depending on what is required.

In addition, in the above embodiment, to calculate the usage fee,
The integrated power amount is multiplied by the set unit price, but a price table corresponding to the integrated power amount is registered in advance in the CPU storage device, and this is selectively read out. It's okay.

In addition, in the above example, the integrated power amount and usage fee are:
Display 4 is designed to switch and display these, but these may be displayed in parallel with separate displays, and in addition to the integrated power amount and 1 renewal fee, the display can also be displayed in parallel. It may be possible to switch the amount and display it.

(F) Effects of the Invention According to the invention, there is provided a current transformer that is connected to a power line to be measured and detects current, and a signal converter that amplifies the current signal detected by the current transformer and converts it into a DC signal. a circuit, a power amount calculation means for calculating power based on the current signal from the signal conversion circuit, an integrated power amount calculation means for integrating the calculated power amount, and performing a predetermined operation on the integrated power amount; Since it is equipped with a usage fee calculation means for calculating the usage fee of the integrated power amount and a display means for digitally displaying the integrated power amount and the usage fee, it is possible to obtain an integrated power meter that is extremely small and compact and can be carried anywhere. Furthermore, installation is easy as all you need to do is connect the power line to be measured to the current transformer.Furthermore, the usage fee is displayed, so no special knowledge of meter reading etc. is required. Anyone can easily use it, and the usage fee can be immediately known if necessary, so it is possible to obtain an integrated wattmeter that is extremely convenient for power management.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a circuit diagram of an integrating wattmeter showing an embodiment of the present invention, and FIG.
The figure is a circuit diagram showing the current transformer connected to the terminals of the integrating wattmeter, Figure 4 is an external plan view of the integrated wattmeter, and Figure 5 is the operation of the integrating wattmeter. It is a flow diagram for explaining. 1: CPU, 3a/3b: Signal conversion circuit, 4: Display,
CT, ・CT2: Current transformer. Patent Applicant Tateishi Electric Co., Ltd. Agent Patent Attorney Shigeru Nakamura Figure 3 Figure 1 Nuh Den 77 Insurance Proceedings Neichi ■ Sansho (Voluntary) September 1988

Claims (1)

[Claims] (1) A current transformer that is connected to the power line under test and detects current, a signal conversion circuit that amplifies the current signal detected by this current transformer and converts it into a DC signal, and A power amount calculation means for calculating power based on the current signal; an integrated power amount calculation means for integrating the calculated power amount;
An integrated power consumption system characterized by comprising a usage fee calculation means for calculating a usage fee for the integrated power amount by performing a predetermined calculation on the integrated power amount, and a display means for digitally displaying the integrated power amount and usage fee. Total.