JPH0267967A - Watthour meter - Google Patents

Abstract

PURPOSE:To detect watthours and consumed charges in a plurality of systems with one apparatus by providing a current-signal receiving part for a plurality of systems comprising current transformers which are connected to power lines to be measured and signal converting circuits which convert the detected currents into DCs. CONSTITUTION:A current transformer 3 of a current-signal receiving part 2 in each system is connected to a power line 1 of respective power system to be measured. Then, a current corresponding to the power in the system flows through each current transformer. The current signal is amplified and converted into AC in a signal converting circuit 4. The value is multiplied by, e.g. preset data in a power computing means 5. Thus the consumed electric energy for every system is computed. The consumed electric energy is integrated in an integrated-power computing means 7 with the elapse of time. Watthours are multiplied by a unit rate which is determined beforehand, for example, in a consumed charge counting means 8. Thus the consumed charge is computed. Then, the consumed watthours and the consumed charge are displayed on a display means 9 in digital values. In this watthour meter, the total watthours and the consumed charge of the power system to which each current transformer is connected are displayed.

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 without meter reading knowledge to obtain usage fees. In addition, conventional integrating wattmeters are fixed-mounted, and usually one is installed for one power supply system, so not only can they not be carried freely, but they can also be used in businesses that have multiple power supply systems. In this case, it was necessary to install an integrating wattmeter for each system.

This invention was made in view of the above problems, and provides an integrated wattmeter that is portable, can be set up anywhere, and can detect the integrated power amount and usage charges of multiple systems with a single device. is intended to provide.

(d) Means and operation for solving the problem The integrating wattmeter of the present invention each includes a current transformer that is connected to the power line to be measured and detects the current, and a current signal that is detected by the current transformer and is amplified. A power amount calculation that calculates the wattmeter of each system based on the current signal taken in from the current signal acquisition unit of multiple systems and the signal conversion circuit that converts it into a DC signal. means, an integrated power amount calculation means that integrates the calculated power amounts of the plurality of systems, a usage fee calculation device that performs a predetermined calculation on this integrated amount of electricity, and calculates a usage fee for the integrated power amount; It consists of display means for digitally displaying the integrated power amount and usage fee (see Fig. 1).

In this integrating wattmeter, when the current transformers in the current signal acquisition section of each system are connected to the power lines of the power system to be measured, each current transformer has a power output corresponding to the power of the corresponding power system to be measured. Current flows. Then, these current signals are amplified and converted into direct current by respective signal conversion circuits, and multiplied by, for example, set data by each power amount calculation means to calculate the power amount for each system. Then, these calculated power amounts are integrated over time by the integrated power amount calculation means. 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. This integrated wattmeter displays the total integrated power amount of the power system to which each current transformer is connected and its usage fee.

(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 CPU, a clock oscillator 2 for generating synchronization signals, and a current signal acquisition unit 1 for two systems.
A display that displays 0 a, 10 b and a 4-digit numerical value (
L E D) 4, a finger drive circuit 6 that drives the digits of the display 4, a segment decoder 7, terminals P3 and P4 receive a commercial voltage of 100 cm, and each circuit receives +12 V and -12 V.
, 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 the power supply voltage, and a CPU
A backup circuit 9 that backs up the memory (RAM) in I, and indicator lights Ll, t, z, ..., L4
and various setting switches SW1, SW2,..., SW
, is composed of.

The current signal acquisition unit 10a includes a current transformer CT coupled to the power line of the power system to be measured (see FIG. 3), and this current transformer C.
It is composed of a signal conversion circuit 3a that receives a current signal from T+, performs signal conversion such as amplification, rectification, and smoothing, and inputs it to the CPUI.

The signal conversion circuit 3a includes an absolute value rectifier circuit composed of operational amplifiers AM, , , AM2, and amplifies, full-wave rectifies, and smoothes the signal corresponding to the detected current input through the terminals Pla and Pem. It has functions.

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 the subsequent stage of the operational amplifier A M t. With this signal conversion circuit 3a,
A current I corresponding to the current flowing through the system under test detected at T
is converted into a DC component and input to the CPUI.

The current signal acquisition unit 10b also includes a current transformer Crt and a signal conversion circuit 3b. The signal conversion circuit 3b is a circuit having the same configuration and function as the signal conversion circuit 3a.

Switches SW1, SW2, ..., 5W10 all use dip switches, among which switch SW1
, SW2, and SW3 are setting switches related to the current transformer CT, and the load power supply voltage is 100V/200V.
This is for setting single-phase/three-phase and current transformer rating of 2OA/100A. Similarly, switch SW
, , SWs , SW are setting switches for the current transformer CT, and are for setting 100 V/200 V, single phase/three phase, and 2 OA/100 A, respectively. The switches SW, SWa, and SWq are used to add and set the unit price. Regarding the unit price, the standard unit price of 18 yen is registered and stored in advance in the CPU, and the switches SW, SWa, and SWq are used to add and set the unit price. W? , SW8
, SW. Set +1 yen, +2 yen, and +4 yen, respectively. Therefore, in this example integrating power meter,
You can set a unit price of 18 yen to 25 yen.

The switch 5W10 is for setting a two-phase detection mode in three phases. The switch SW,i is a reset switch, and the switch SW1□ is a display switch.

0N of switches SW1, SW2, ..., SW, z
The 10FF state is imported into the CPUI.

The CPU has an A/D conversion function, a function of converting the current signal l into a digital signal and capturing it from two series of current signal capture units 10a and 10b, and a switch SW.
・, SW3 and SW4, ..., SW.

It has a function of reading reference data determined by the setting conditions 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 the amount of power output when a current signal corresponding to 1 bit is input from the A/D converter, and the reference data is the amount of power outputted when a current signal corresponding to 1 bit is input from the A/D converter.
00 V, single phase/three phase, 2OA/100A 8
The type is memorized. Now, for example, A/D change tA2K
If the current transformer CT is set to 200cm, 3-phase, 2OA, then the reference data D is:
However, the power factor is fixed at 0.85.

The CPU further has a function that calculates the cumulative power amount by 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 multiplying the calculated cumulative power amount by the set unit price, and 0N of switch SW1□.
It has a function of switching and displaying the integrated power amount and usage fee on the display 4 according to the 10FF setting status.

Indicator light I lights up when the display is switched to fare. This indicator light has a weight of 100 yen. Therefore, if the indicator light 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 L3,
For L4, the specifications of current transformers CT, CT, and CT are 100, respectively.
A, and lights up when the switches SW: I 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,
Indicator lights L1, L2, reset button S W I I l
, display switching buttons SW+z- are arranged so as to be visible to the naked eye, but the other circuit sections shown in FIG. 2 are housed within the main body case 20.

Buttons 5Wz-, SW+□, main body case 20
The reset button SW + + - cannot be operated unless the main body case 20a is removed, and the display switching button SW1g cannot be operated unless a bar or the like is inserted into the small hole 20b. ON10
This prevents FF from being touched, preventing erroneous settings caused by easy touching.

When using this embodiment of the integrated power meter, the current transformer CT t
and a current transformer CT, respectively, are inserted and coupled to one of the load power lines to be measured (for example, see FIG. 3). Then, the settings for each current transformer CT, CT2 are changed to switch SW,... If the power system is different,
There may be different settings for double flow devices. Therefore, regarding the current transformer CT, the switch SW is set to the 100■ side, whereas the switch SW by the current transformer CT2 is set to the 100■ side.
The setting of 4 can also be set to 200■, and while the setting by switch SW2 is three-phase, the setting by switch SW may be single-phase. However, in the case where the double flow transformers CT, CT2 are each coupled to one of the same three-phase load power lines,
When detecting a current signal corresponding to the amount of electric power by each of the electric signal acquisition units 10a and 10b, and averaging the amount of electric power obtained based on this, that is, switch SW. In the case of two-phase detection in three phases when is turned ON, it is necessary that the current transformers CT, , CT have the same condition settings.

After coupling the current transformers ICT, , C70 to the respective intended load power lines, the corresponding settings of the respective current transformers CT, , C70 are changed to the switches SWl, . . . , SW, respectively.
Do it with

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 SW? , SW
All you have to do is turn off both e and SWq.On the other hand, if you want to set the unit price to 25 yen, turn off the switch S.
W7, S We, and S W9 are all 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], then it is determined whether a counter reset is requested (Sr2).

Here, the counter reset request is a request to set the count value for counting the integrated power amount to O, and
, , are 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. Sr2 judgment 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 0 (5T4), the contents of the counter are converted to BCD (5T5), and the display stack is Perform the operation (Sr1). 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.
0 will be displayed. After that, the process moves to ST7. On the other hand, if the reset request flag is 0 in Sr2, this determination becomes No, and the process jumps to Sr7, where it is determined whether or not there is a display switching request.

Here, the display switching request means that when the switch SWI□ is turned ON, a switching request flag is set due to an interrupt caused by this 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. If there is a switching request, clear the switching request flag with Sr8, and when switch 5W12 is turned on while indicator lamp L2 indicating kilowatt hours is initially lit, indicator lamp L+ is turned on. Performs LED display processing (Sr1), performs BCD conversion processing for the charge calculated by the charge counter (STIO
), this converted usage fee data is operated on a display stack (STII), and the usage fee is displayed on the display 4 in units of 100 yen. In Sr7, if the indicator light is on before switching the display, that is, if the display is the usage charge display, the LED display process in Sr1 switches the indicator light L2 to light, and similarly, the BCD of 5TIO1STII is switched on. Conversion processing and display stack operations are performed, and the cumulative amount of power used 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 execution output is set.

This running output cell I is sent for testing purposes. Subsequently, in 5T14, A/D conversion processing is performed, and the current inputs detected by the current transformers CT and CT2 taken in from the signal conversion circuits 3a and 3b are respectively taken in and stored. It is determined whether or not power integration is to be stopped (ST15). This power integration stop occurs before the power integration counter counts up.
This is detected and an error is displayed. If the power integration is to be stopped, the process moves to 5T2B, 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 input refers to the setting conditions of each current transformer CT, CT, from switch SW to switch SW6, and switch SW9,...
·, SW, the additional amount of charges, and the 0N10FF signal of the 3-phase 2-wire processing of the switch SW1°, etc. followed by 3
Determine whether there is a phase 2 wire setting error or not. 5T17), 3 phase 2
In the case of a line Bλ constant error, the process also jumps to 5T2B.

The conditions for determining a 3-phase 2-wire setting error are: 3-phase 2-wire detection switch SW1° is ON T Varnish 4 Switch SW3, SW
This is a case where ON10 FF of & 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 (STlB). 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 ON, the normal 2
This is the process of detecting the power amount of the series. Therefore, first a calculation set is performed for the current transformer CTl (ST19), and reference data corresponding to each setting condition is applied to the current value taken in through the signal conversion circuit 3a and the input terminal AN. The power of the power system to which the current transformer CT is connected at this point in time is calculated (ST20). After the reset, the integrated power amount stored in the RAM counter until then will be changed to
The power amount calculated this time is integrated (ST21). next,
Next, we will perform a set of calculations regarding the current transformer CT (ST
22) Similarly, calculate the power of the power system to which the current transformer CT is connected, and calculate the current transformer CT and CT,
The integrated power amount of the power system related to the current OCT is integrated with the integrated power amount of the current OCT, 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. If the determination of 3-phase 2-wire detection is YES in 5T18, in 5T23, the current signal taken in from the current signal acquisition part 10a and the current signal taken in from the current signal acquisition part 10b, Calculate the power for each system and average the results. Then, this average value is integrated (ST2
4). In the case of three-phase two-wire detection, since averaging processing is performed, more accurate determination can be made. Next, it is determined whether the usage fee exceeds one million yen (Sr16), 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 (S
T28). In this case, LED display processing is also performed in the same way (ST
29). 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, when an error occurs, such as when the display is not normal, such as when the integrated power value is stopped, or when the judgment is YES if it exceeds a million yen, a flashing light or a special display will be displayed to indicate the respective situation. Become. S
When the LED display process of r11 is completed, the execution request flag that has been turned on until then is cleared (5T30), and backup judgment data is set (ST31). Here, the backup judgment data is data set in the CPU ORAM 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, the processes from Sr1 to Sr1 are performed, and if there is a request to switch the display, , Sr7 to 5TII are processed, and if there is an execution request every 1 second, 5T
The processes from 12 to 5T32 are repeated, and the power of each power system is calculated every second, and the current calculated power amount is added to the previous integrated power amount, and the charge for the total integrated power amount is calculated. Perform calculations and continue working.

Note that in the above embodiment, two lines of electric power intake units consisting of current transformers and signal conversion circuits are provided, but the present invention is not limited to this, and three or more lines may be provided. Good too.

In addition, the setting switches SW + to SW each set two types of conditions for the current transformer, but they can also be used to select and set three or more types of conditions depending on what is required. It's okay.

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:
The display is switched and displayed on the display 4, but these may be displayed in parallel with separate displays, and in addition to the integrated power amount and usage fee, the power amount can also be displayed in parallel. The display may be switched and displayed.

(F) Effects of the Invention According to the present invention, a plurality of current signal acquisition sections each consisting of a current transformer and a signal conversion circuit, and a current signal acquired from each current signal acquisition section are used. A power amount calculation means that calculates the power amount of each system, an integrated power amount calculation means that integrates the calculated power amounts of multiple systems, and performs a predetermined calculation on the integrated power amount, and charges usage charges for the integrated power amount. and a display means for digitally displaying the integrated power amount and the usage fee,
You can get an integrated wattmeter that is very small and compact and can be carried anywhere.Furthermore, it is easy to install as all you need to do is connect the power line to be measured to a current transformer, and what's more, usage charges are displayed. Anyone can easily use it without any special knowledge of meter reading, etc., and can immediately know usage charges as needed, making it an extremely convenient integrated power management system. You can get the meter.

Furthermore, since it is provided with a plurality of current signal acquisition units, it is possible to know the integrated power amount and usage fee of different power systems for each unit.

[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 part connected to the terminals of the integrating wattmeter, Figure 4 is an external plan view of the integrating wattmeter, and Figure 5 shows the operation of the integrating wattmeter. It is a flow diagram for explanation. 1: CPU, 3a-3b: Signal conversion circuit, 4: Display,
CT, ・CT,: Current transformer, 10a/10: Current signal acquisition section. Den 77 Chen Diagram 1 Patent Issuer Tateishi Electric Co., Ltd. Agent Patent Attorney Shigeru Nakamura

Claims (1)

[Claims] (1) Current signals of multiple systems, each consisting of a current transformer that connects to the power line under test and detects the current, and a signal conversion circuit that amplifies the current signal detected by the current transformer and converts it into a DC signal. an acquisition section; an electric energy calculation means for calculating the electric energy of each system based on the current signal acquired from each current signal acquisition section; an integrated power amount calculation means, a usage fee calculation device that performs a predetermined calculation on the integrated power amount to calculate a usage fee for the integrated power amount, and a display device that digitally displays the integrated power amount and usage fee. Total.