TW388794B - Power measuring method for detecting and preventing power theft - Google Patents

Abstract

The invention relates to a power measuring method for detecting and preventing power theft, which primarily utilizes a wattmeter having switchable voltage wires to measure two sets of currents and voltages of a three-phase power source and the two sets of currents and voltages are measured to determine if there is a difference in the power factor angle. If yes, an illegal capacitor is present, and the wire connection of the wattmeter is changed. As such, a special wire connection is used to enable the wattmeter to correctly measure the power consumption, and a suitable indication device is employed to notify of such power theft.

Description

Printed by Shellfish Consumer Cooperative of Central Bureau of Standards of the Ministry of Economic Affairs Λ7 ---------- B7 V. Description of Invention (/) ～~ ~ --- This invention relates to a type that can detect and prevent power theft. The method of electricity measurement, especially a kind of electricity user who misuses the capacitor to make the meter inaccurate and the electricity is stolen, can still accurately measure the actual power consumption 'and display its electricity theft incidents. Electricity companies are mainly based on electricity meters. Record the electricity consumption of the users and charge the users accordingly, but some unscrupulous users still try to use improper practices to steal electricity and pay the electricity short. This not only seriously affects the principle of fairness, but also causes great losses to the power company. Regarding the current methods of recording power consumption and the stealing of electricity by some unscrupulous users, I would like to further explain the following: Electric power companies generally use "watt-hour meters" to record the power consumption of loads, and a two-phase two-wire two-element type watt-hour meter system It is used to measure three-phase electric power. The two-phase two-wire two-element watt-hour meter sets two sets of single-phase electric meters on the same rotating shaft. When the current passes through the electricity, the torque of the rotating shaft will be changed. Rotate to display the metering index. As shown in the sixth figure, it is the aforementioned watt-hour meter (80) and its two sets of power meters (81) (82) connected to the three-phase power terminals i, 2, 3, and the load through an external connection wire, respectively. Connection, where the power meter (8 1) is connected between the 1st and 2th phase power supply, and the other power (8 2) is connected between the 3rd and 2th phase power supply. The vector analysis system according to the aforementioned connection method is as the seventh As shown in the figure: where Vl2, V23, V31 are the voltage between the lines I 1 '12, I 3 is the current between the lines, and P is the power factor angle of the load

When the load is balanced, V12 = V23 = V3I = V

Il = l2 = l3 = I _______ _3_ This paper size is applicable to the national standard (CNS) A4 (21GX297 mm) of the paper towel ~ ---- {Please read the precautions on the back before filling this page s_, -Order Printed by Shellfish Consumer Cooperative, Central Standards Bureau, Ministry of Economic Affairs Λ7 B7 V. Description of the invention (>) P = Pi + P j = V uli cos (30o + φ) + V32I3 cos (30 ° — φ) = Vl [cos 30 ° cos φ-sin 30 ° sin φ + cos 30 ° cos φ + sin 30 ° sin φ] = λ / 3 VI cos φ The P value in the foregoing formula is the electric power in the normal measurement mode. However, when the user improperly uses the capacitor at the load end, it will cause the watt-hour meter (80) to be inaccurate, and the purpose of short-term payment of electricity bills will be achieved. According to the application of capacitors in power supply, it is mainly used to improve the power factor. Therefore, power companies often install capacitors at every interval of power transmission, and for users, 'connecting a capacitor on the power supply side can also modify the power supply. Inductive phase difference and further improve its power factor. However, the improper use of the aforementioned capacitors for stealing electricity is not used to improve the power factor. Its connection method is shown in Figure 8 (which is a positive phase sequence power supply method). The third phase power supply at the load end is connected to ground. A capacitor (90), the capacitor (90) will then cause the Watt-hour meter (80) to be inaccurately measured, and its electrical power measurement error can be obtained by the following formula conversion:

l3 ’= I3 + I3SC V.2 = VM = V31 = V

Λ = λ1 + λ3 I, = l2 = l3 = I = V nil cos (30 ° + φ) + ν32ι3 · cos φΑ = V12I1 cos (30 ° + φ) + V32Ι3 cos (30 °-φ) + V32I3SC cos 150 °

= V3 VI cos φ-~ VI3SC

= P ---- VI3SC 2 In the foregoing formula? * It is the electric power measured by the watt-hour meter (80) under the condition of improperly connected capacitor (g 〇) at the load end. It can be known from the above conversion that the improperly connected capacitor (90) will appear as Vl3SC. Difference, this difference in electric power is the theft of the user without paying a fee (please read the precautions on the back before filling this page) -ο-

A

Printed by the Central Bureau of Standards of the Ministry of Economic Affairs and Consumer Cooperatives PNS) λλΤΓΊΓΤ · Λ 7 B? 5. Description of the invention (J) Power consumption. According to the understanding, there is a gradual increase in the number of large consumers who use the aforementioned methods to steal electricity, causing serious losses to power companies. It can be seen that the existing methods of metering electricity consumption have been obviously neglected and need to be further improved. Therefore, the main purpose of the present invention is to provide a method for accurately measuring the actual power consumption when the user improperly connects the capacitor to steal electricity, and Electricity metering method showing the fact of stealing electricity. In order to achieve the foregoing objectives, the main technical measures adopted by the present invention include: a step of separately detecting two sets of voltage and current signals in a three-phase power supply by an electric meter with switchable voltage junctions; and a power factor angle for judging the two sets of signals. Steps of whether there is a difference; One is the step of switching the voltage connection of the meter to measure the normal power consumption when there is a difference in the power factor angle of the two sets of voltage and current signals; One is to start the indicating device synchronously when the voltage line of the meter is switched Steps to show users the fact of stealing electricity. Another technical means adopted by the present invention is a three-phase three-wire two-element electric meter connected between the power end and the load end, wherein the voltage coil of the electric meter is provided with a relay to control its connection switching; the relay is controlled by a Unit controlled. Another technical means adopted by the present invention is that the aforementioned control unit includes a voltage signal detection circuit connected to a power source for detecting a voltage signal; _____ 5 This paper size is applicable to the Chinese national clothes De Ang f (Please read the precautions on the back before (Fill in this page) Order · Printed bags of the Central Bureau of Standards, Ministry of Economic Affairs, Shellfish Consumer Cooperatives Λ? —________________ V. Description of the invention (〆) A current signal detection circuit connected to a power source through a current transformer for detecting a current signal ; A microprocessor for judging the phase sequence of the power supply and the voltage and current signals and their phases; an instruction unit driven by the microprocessor based on the judgment results of the voltage and current signals for indicating whether an electric power theft occurs; of which the microprocessor At the same time, control the relay to switch the meter's wiring. 'When the voltage and current signal detection circuit detects two sets of voltage and current signals, the power factor angle difference' can be used to determine that the user has stolen electricity. Measure the correct power consumption. In order to make your reviewing committee better understand the foregoing purpose and the technical means of the present invention, detailed drawings are attached as follows: (1) Schematic part: The first figure: the meter wiring diagram used by the present invention to correctly detect electric power . The second figure is a schematic diagram of the structure of capacitors improperly used under the aforementioned meter junction structure. Third 囷: This is the wiring diagram of the present invention used to make electricity expression for the purpose of wire switching. 〇 Fourth diagram: This is the control unit circuit diagram of the present invention used to detect voltage, current signals and control the meter's wire switching. Fig. 5 is a flowchart of the operation of the present invention. Figure 6: Schematic diagram of the knot of a conventional watt-hour meter. Figure 7: Vector analysis diagram of three-phase power supply. The eighth figure is a schematic diagram of the connection of improper use of capacitors at the load end. ___6___ This paper size applies Chinese National Standard (CNS) Α4 size (21〇 × 297 mm) (锖 Please read the precautions on the back before filling in this page)

Λ7 V. Description of the invention (r) (II) Drawing number: (10) Micro-processing g (20) Voltage signal detection circuit 2 1) (22) H (3 Q) Current signal detection circuit 2 3) (2 4) (3 3) (3 4) Operational amplifier (31) (32); Wave wave circuit (4〇) Relay medium circuit (41) Relay (42) Buffer relay "11) (412) (421) (422 ) Switch contact (43) (44) light coupler (50) indicating unit (51) (52) light coupler (60) power circuit (53) (54) light emitting diode (80) ) Watt-hour meter (81) (82) power meter (90) capacitor (8 1 1) (812) (821) (822) coil The power measurement detection method of the present invention generally includes the following steps: Steps for voltage-connected meters: three steps of two sets of voltage and current signals in a three-phase power supply;-steps to determine whether there are differences between the two sets of signal power factor angles (power factor angles); printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs Intensive installation-yi \ (Please read the precautions on the back before filling this page)-When there is a difference in the power factor angle between the two sets of voltage and current signals, switch the voltage connection of the meter to measure the normal power consumption; First, when the voltage line of the meter is switched, the step of synchronously starting the indication device to display the fact that the user has stolen electricity. Do not mention the first step is that the meter is connected to the power end and the load end by the traditional connection method, and obtains two address voltage signals and two groups respectively. Current signal, which

Only the scale is applicable to the professional standards (CNS V. Invention Description (厶) The wiring method is as shown in the sixth figure. There are two sets of power meters (81) and (82) on the watt-hour meter (80)). Coil (811) (8 12) (821) (822), where the coil (811) (8 2 1) is directly connected between the power end and the load end to supply the current between the induction wires, and the coil (812) ( 822) are respectively connected between the 1st and 2nd phase power supplies and the 3rd and 2th phase power supplies to sense the voltage between the lines. As described in the previous disclosure, such connection methods such as improper connection of a capacitor at the load end (9 0) ( (As shown in the eighth figure), will make the watt-hour meter (8 ◦) measurement inaccurate. Regarding the other improper connection capacitance conditions, the present invention obtains two sets of voltage and current signals and judges the difference in power factor angle between the two. Based on the detection (that is, the second and third steps described above), because the user steals electricity from the third-phase power supply connected to the load and the grounded indirect capacitor (90), the third and second-phase power supplies obtain the power factor of the electric current number. The angle will be quite different from the power factor angle of the voltage and current signals obtained by the first and second phases (ideally, the two sets of voltage and current signals The power factor angle should be the same), so we only need to judge whether the power factor angle of the first group of voltage and current signals (between phases 1 and 2) is not equal to the second group of voltage and current signals (phases 3 and 2), that is, It can detect whether there is any power stealing at the client .. Printed by the Central Samples Bureau of the Ministry of Economic Affairs, Shelley Consumer Cooperative. When the client is detected with power stealing, the present invention allows the meter to change another connection mode, which can effectively prevent The theft structure caused by improper use of capacitors 0), the connection structure is shown in the first figure: the two sets of power meters (8 i) (82) of the watt-hour meter (80) still use coils (8 1 1) (8 2 1) is directly connected in series between the power terminal 丄, phase 3 and the load terminal for inducing current between the wires, and the other end is connected to the __ 8 This paper size is applicable to the Chinese National Standard (CNS) Λ4 蚬 Grid (210X $ 297 ------- Λ7 Λ7 V. Description of the invention (The coil of the phase power supply terminal (8 1 2) is connected to the ^ th load terminal with the other end, and the other end is connected to the coil of the 3rd phase power supply. (8 2 w is connected to the load terminal of phase 3 to sense the wires of phase… "mesh two" power respectively. Voltage at the end-line, provided ν12 = ν23 = ν31 = ν, by the time the watt-hour meter (8 Ο) electric power is measured dagger

Pb = Pbi + Pb3 = V uli cos (30 °-φ) + V3il3 cos (3〇 ° + φ)

= λ / 3 VI cos φ = P Under the aforementioned junction structure, if the user improperly connects the capacitor (9 0) at the load end (as shown in the second figure), the electric power Pc measured by the watt-hour meter (80) Can be learned from the following formula:

Pc = Pci + PC3 = Vnli cos (30 °-φ) + V31I3 'cos (30 ° + φ) = Vuli cos (30 °-φ) + VmL · cos (30 ° + φ) + V3iI3Sc cos 90 °

= V3 VI cos φ = P Printed by the Shellfish Consumer Cooperative of the Central Guiding Bureau of the Ministry of Economy From the above, it can be known that under the aforementioned wiring structure, even if the user improperly uses the capacitor at the load end, it will not cause the correct amount of watt-hour meter (80). Impact. In addition, in addition to using the foregoing wire connection method to enable the watt-hour meter (80) to accurately measure the power consumption of the user terminal, the present invention will further detect and display the user's illegal power stealing for reporting purposes. Therefore, the present invention obtains two sets of voltage and current signals at the traditional junction of the watt-hour meter (80). When a difference occurs between the two sets of voltage and current signals, it means that the user terminal has used the capacitor to steal electricity. Then the present invention Paper size applies to Chinese National Standard (CNS) Α4 size (210X 297 gigabytes) Printed by the Consumers' Cooperative of Central Standards Bureau of the Ministry of Economic Affairs Λ7 Β7 V. Description of the invention (丨) Conversion of the electric hour meter (8 Q) to the electrical connection In order to obtain the positive broken juice 4 that is not affected by the capacitor, go forward-step cents and display the message of power stealing for investigation. Firstly, in the structure of a hard ship implementing the aforementioned method, first, as shown in the third figure, the electronic contact point of the relay 11 (4 1) can be used to switch the aforementioned watt-hour. Ten (80) electrical i-connections are used to switch between the two aforementioned connection configurations, and a control unit controls the operation of the relay (i0). The circuit diagram of the control unit is shown in the fourth figure, which includes a microprocessor (1Q), a voltage detection circuit (2) that detects a voltage signal from the power supply terminal and sends it to the microprocessor (1). 1. A current detection circuit (30) that detects the current signal from the power supply through the current transformer and sends it to the microprocessor (Industrial Q); a relay drive circuit (40) controlled by the microprocessor (10); An indication unit (50) and a power circuit (60); wherein: the voltage detection circuit (20) is mainly composed of two sets of transformers (2 1) (2 2), two sets of operational amplifiers (2 3) ( 2 4), and two transformers (2 1) (2 2)-the secondary side is respectively connected to the RST phase (ie, phases 1, 2, and 3) of the power supply side, and the secondary side is respectively connected to the operational amplifier (2 3) The positive terminal input of (24), and the output terminals of the two operational amplifiers (2 3) (2 4) are respectively connected to the microprocessor (10), used to convert the voltage signal in the form of a sine wave into a square wave The signal is used by the microprocessor (10) to calculate its size and phase. In other words, the aforementioned voltage detection circuit (20) will detect two sets of voltage signals from the first, second, and third phase (RST) phase power supplies, respectively. The paper size is suitable for financial and family transfer (⑽) 6 4 specifications (21 () × 297 Gongnong

V. Description of the invention (/) The current consumer detection circuit (30) printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economics is composed of two sets of filter circuits (3 1) (32) and two sets of operational amplifiers (33) (34) ), Where the two filter circuits (31) and (32) are connected to the R phase and T phase of the power supply terminal through a current ratior (not shown) respectively to detect the current ^ 'and the filter circuit (31 ) (32) The output end will be connected to the positive input of the operational amplifier (33) (34), and the output end of the operational amplifier (33) (34) will be connected to the microprocessor (10) to convert it into a square wave The current signal in the form is sent to the microprocessor (10) for calculation and judgment of the magnitude and phase of the current. Therefore, the aforementioned current detection circuit (30) will respectively detect two sets of current signals from the first and third phase (R, T phase) power supplies. The microprocessor (10) will check the power supply in the form of positive phase sequence or reverse phase sequence through the aforementioned voltage detection circuit (20) and current detection circuit (30), and will detect the two sets of voltage and current detected by the two. The signal judges whether the user terminal has a power stealing situation. The relay driving circuit (40) includes a relay (41), a buffer relay (42), and two sets of smooth surface couplers (43) (44) connected to the relay (41) and the buffer relay (42). The optical coupler (4 3) (44) is used for isolation, which is connected to the two output terminals (RLSW0, RLSW1) of the microprocessor (1 0); the relay (4 1) and the buffer relay (4 2) There are two sets of switch contacts (4 11) (412) (421) (422), of which the common end of the relay (411) (412) is connected to the line of the two power meters (81) (8 2) (8 1 2) (8 2 2) connection, one of its contacts (normally open paper size is applicable to China National Standard Car (CNS) Λ4 specification (210 dogs 297)) ----- (Please read the precautions on the back first Fill in this page again) Install Λ7 Λ7 Printed by the Central Samples Bureau of the Ministry of Economic Affairs, Shellfish Consumer Cooperatives. V. Description of the invention (connected to the power supply: R, T phase, and-contact (normally closed) is connected to the relay (42) The upper two switch contacts (421) " 2 points at the same end, one of the two switch contacts (4 2 1) (4 2 2)-connected. Khan is empty to connect the other contact (normally closed) to s Phase. = Mentioned relay (4 1) It is mainly used to switch the watt-hour meter (80) :: crimping wire, and the buffer relay (42) is the aforementioned switching wire for pre-buffering. Because of the coil (8 2) of the power meter (81) (82) (8 2 2) At the moment when the power is cut off, a large back-EMF voltage may appear. To prevent circuit damage, the microprocessor (10) will order the buffer relay (42) before the drive relay (41) is switched. , The switch contact (421) " 22) is cut to the empty contact, and then the relay (4 1) is switched for connection, and then the contact of the buffer relay (4 2) is restored, so that the circuit can be protected from the impact of the back electromotive voltage The indicating unit (50) is mainly composed of two groups of isolated photocouplers (51) (5 2) and two groups of light emitting diodes (5 3) (5 4), of which the photo coupler (51) ( 52) The input terminal is connected to the microprocessor (1 0) output terminal (PH LED, PL LED), and the two light emitting diodes (5 3) (5 4) are different colors and can be divided to display normal or abnormal (ie There is power stealing). In addition to the indication unit (50), it can also be a different form of alarm device. The processing workflow of the processor (10) is shown in the fifth figure. It first determines the phase sequence of the power supply (that is, the order of R, S, and D), and determines whether the power supply is positive phase sequence or reverse. After the phase sequence, it began to judge 12 paper sizes that are applicable to the Chinese National Standard (CNS) Λ4 specification (210X297). ^ --- η, installed ------ " ------ like / V ( "(Please read the precautions on the back before filling this page) Λ R- V. Description of the invention (//) Whether the capacitor is used improperly by the user end, the judgment step is determined by the microprocessor (1〇) the voltage detection circuit ( 2 0) and the current detection circuit (3 0) whether the two sets of electric current signals have a power factor angle difference. If the two sets of electric current signals have the same or very close power factor angles, it means that the user terminal is not used improperly. Conversely, if there is a difference in the power factor angle between the two sets of signals, it means that the user has used the capacitor improperly, and the microprocessor (i Q) will change the connection form of the watt-hour meter (80) through the relay (41) (such as the first (As shown in the figure) to measure the correct power consumption, at the same time, the drive instruction unit (50), Light display for the user improper use of capacitors conditions, for use as a check of the newspaper. As can be known from the above, the present invention provides a power measurement method capable of detecting and preventing power theft. With this design, even when a user improperly connects a capacitor to perform power theft, the user's actual power consumption can be accurately measured to In addition to preventing theft of electricity, in addition to this, the present invention further detects whether the user has a situation of stealing electricity for reporting purposes, thereby achieving the purpose of effective resource management and preventing illegality. It is clear that it has already possessed industrial applicability and progress, and met the requirements of invention patents. Packing-./V (Please read the precautions on the back before filling out this page) Order · Printed by the Consumers' Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 13 f The paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm)

Claims (1)

.- A kind of power measurement method that can detect and prevent theft of electricity, which includes: Using a switchable voltage junction meter to separately detect two sets of voltage and current signal power factor angle steps in a three-phase power supply; Steps of whether the power factor angle of the two groups of signals has a difference; When the power factor angles of the two groups of voltage and current signals are different, the step of switching the voltage of the meter to measure the normal power consumption; Hours' synchronous start instructs the device to show the user the fact of stealing electricity. 2. As described in item i of the scope of patent application, a power measurement method capable of detecting and preventing power theft can be performed by a control unit, the control unit includes: a voltage connected to a power source for detecting two sets of voltage signals Signal detection circuit; a current signal detection circuit connected to the power supply through a current comparator for detecting two sets of current signals; a microprocessor for judging the phase sequence of the power supply and the power factor angle difference between the two sets of voltage and current signals Printed by the Central Government Bureau of the Ministry of Economic Affairs, Shellfish Consumer Cooperative (please read the precautions on the back before filling this page)-a microprocessor-controlled relay drive circuit to switch the watt-hour meter voltage wiring;-a microprocessor based on the voltage The current signal judgment result is driven to provide an indication unit for displaying whether there is an electricity stealing event; the aforementioned microprocessor will control a relay through the relay drive circuit to switch the voltage connection of the watt-hour meter. 14 ¥ Paper size: Chinese «Home Standard (CNS) A4 size (210X297 male jTj " " A8 B8 C8 _____ D8 VI. Patent application scope 3) Detect and prevent theft as described in item 2 of patent application scope Electric power metering method, the relay driving circuit further includes a buffer relay, which is connected between the power supply terminal and the relay as a buffer isolation function. 4. It can detect and prevent as described in item 1 or 2 of the scope of patent application. The power metering method for stealing electricity, the indication unit is composed of light-emitting diodes. 5 · As described in the second scope of the patent application, a power metering method for detecting and preventing electricity theft, the voltage signal detection circuit is composed of two A transformer and an operational amplifier connected to the secondary side of the transformer by a positive input, wherein the primary side of the transformer is connected to a three-phase power supply, and the output end of the operational amplifier is connected to a microprocessor. The electric power measurement method that can detect and prevent theft according to 2 items. The current signal detection circuit is composed of two sets of filter circuits and a positive input and a filter output respectively. Connected operational amplifiers, where the input end of the filter circuit is connected to the power supply through a current transformer, and the output end of the operational amplifier is connected to the microprocessor. 7-A power metering device that can detect and prevent power theft, It includes: a voltage signal detection circuit connected to the power supply for detecting two sets of voltage signals; a current signal detection circuit connected to the power supply through a current comparator for detecting two sets of current signals; one for determining the phase of the power supply Sequence and two sets of microprocessors with the same power factor angle of voltage and current signals; one relay driven by the microprocessor to switch the watt-hour meter voltage and wiring 15 drive standards applicable to China's national standard &CN; A4 Regulation 210X297 (%) ~ &Quot; / HV (Please read the note $ on the back before filling out this page 'Binding-Order-Spring-Printed A8 B8 C8 D8 Consumer Cooperative Cooperative by the Central Bureau of Standards of the Ministry of Economic Affairs 6. Scope of Patent Application A moving circuit; an instruction unit driven by a microprocessor based on the results of voltage and current signals for indicating whether an electric power theft has occurred; let alone the microprocessor drives it through a relay The circuit controls a relay to switch the voltage connection of the watt-hour meter. 8 'As described in item 7 of the scope of the patent application, a power metering device that can detect and prevent power theft, the relay drive circuit includes a buffer relay that is connected to a power source Between the terminal and the relay, as a buffer isolation function. 9 · As described in item 7 or 8 of the scope of patent application, a power metering device that can detect and prevent theft of electricity, the indicating unit is composed of a light emitting diode. 0 · As described in item 8 of the scope of the patent application, a power metering device capable of detecting and preventing theft of electricity. The voltage signal detection circuit is composed of two sets of transformers and an operational amplifier connected to the secondary side of the transformer with a positive input. The primary side of the transformer is connected to a three-phase power supply, and the output of the operational amplifier is connected to a microprocessor. 1 1 · As described in item 8 of the scope of the patent application, a power metering device capable of detecting and preventing theft of electricity. The current signal detection circuit is composed of two sets of filter circuits and a connection between a positive input and a filter output. The amplifier, wherein the input end of the filter circuit is connected to the power supply through a current transformer, and the output end of the operational amplifier is connected to the microprocessor. 16 This paper uses China National Standard (CNS) A4 size (210X297 mm) -------- r.; Installed-(Please read the note ^^ on the back before filling this page) , 11 '., Quan-Printed by the Consumer Standards Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs «.