CN112285638A - Misalignment online monitoring device for multi-channel electric energy meter - Google Patents
Misalignment online monitoring device for multi-channel electric energy meter Download PDFInfo
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Abstract
The invention provides a multichannel electric energy meter misalignment online monitoring device which comprises an electric quantity metering unit, an electric meter reading unit, a channel identification unit and an error judgment unit. After the pairing relation between the electricity consumption in the electricity metering unit and the electricity consumption records of the electric energy meters is determined, the accuracy of the electricity metering unit is higher than that of all the electric energy meters, so that the metering accuracy of the electric energy meters can be evaluated by reading of the high-accuracy electricity metering unit, the plurality of electric energy meters can be monitored in an inaccurate online mode, each unqualified electric energy meter can be identified, the qualified electric energy meters are prevented from being replaced, resources are saved, and the labor and logistics cost are reduced.
Description
Technical Field
The invention relates to the technical field of misalignment monitoring of electric energy meters, in particular to a multichannel electric energy meter misalignment online monitoring device.
Background
In recent years, the economy of China is developed at a high speed, the popularization rate of the intelligent electric energy meter is higher and higher, and the application of the state evaluation technology of the electric energy meter is wider and wider. The intelligent electric energy meter state evaluation technology is divided into a batch life estimation early warning technology and an online metering state evaluation technology. The method is characterized in that a batch life estimation early warning technology of the electric energy meters is generally used, an electric power enterprise registers the electric energy meters installed on site according to production batch, installation date and the like, then sampling detection is carried out in a certain period according to relevant verification regulations of the enterprise, and if the proportion of unqualified electric energy meters in the verified electric energy meters reaches an early warning line, the electric energy meters in the same batch of the same manufacturer are judged to have problems and need to be replaced in the whole batch. In this way, the electric energy meters qualified in the inspection can be replaced in the batch, which is not beneficial to energy conservation and environmental protection and wastes social resources; and the table replacement causes the old table to be disassembled and processed, and the work of purchasing and installing the new table and the like generates huge increase of manpower and logistics cost.
Disclosure of Invention
In view of this, the invention provides a misalignment online monitoring device for a multi-channel electric energy meter, so as to solve the problem that the conventional misalignment online monitoring device for the electric energy meter cannot identify each unqualified electric energy meter.
The technical scheme of the invention is realized as follows: a multi-channel electric energy meter misalignment online monitoring device comprises an electric quantity metering unit, an electric meter reading unit, a channel identification unit and an error judgment unit;
the electric quantity metering unit is connected with each electric energy meter in series through different distribution lines respectively and is used for collecting electric signals flowing through each distribution line and calculating the electricity consumption according to the electric signals, and the precision of the electric quantity metering unit is higher than that of all the electric energy meters;
the electric meter reading unit is respectively connected with each electric energy meter through different data buses and is used for reading the address of each electric energy meter through the data buses by utilizing a bit reduction address method and acquiring the electricity utilization record of each electric energy meter according to the address of each electric energy meter;
the channel identification unit is respectively connected with the electric quantity metering unit and the electric meter reading unit and is used for acquiring the electric quantity data of each electric energy meter according to the address of each electric energy meter and determining the distribution lines corresponding to the addresses of each electric energy meter according to the electric signals of each distribution line and the electric quantity data of each electric energy meter;
the error judgment unit is respectively connected with the electric quantity metering unit, the electric meter reading unit and the channel identification unit and used for calculating the metering accuracy of the electric energy meter corresponding to each distribution line according to the electric quantity and the electric record corresponding to each distribution line.
Optionally, in the channel identification unit, the power distribution line corresponding to the address of each electric energy meter is determined according to the electric signal of each power distribution line and the electric quantity data of each electric energy meter, including;
acquiring a current instantaneous value and a voltage instantaneous value in the electric signal, calculating the active power P1 of the corresponding load of each distribution line according to the current instantaneous value and the voltage instantaneous value in the electric signal, and acquiring an active power sequence between sampling moments t 1-t 2
P1；
Acquiring a current instantaneous value and a voltage instantaneous value in the electric quantity data, calculating the active power P2 of the corresponding load of each electric energy meter according to the current instantaneous value and the voltage instantaneous value in the electric quantity data, and acquiring an active power sequence between sampling moments t 1-t 2
P2；
According to the active power sequence corresponding to each distribution line
P1 and active power sequence corresponding to each electric energy meter
P2 identifies the power distribution line corresponding to the address of each power meter.
Optionally, in the channel identification unit, the power distribution line corresponding to the address of each electric energy meter is determined according to the electric signal of each power distribution line and the electric quantity data of each electric energy meter, and the method further includes:
respectively calculating active power sequence
P1 and active power sequence
Discarding the active power sequence at power increment between any two adjacent power points in P2
P1 and active power sequence
And power points corresponding to all power increments conforming to the normal distribution in P2.
Optionally, in the channel identification unit, according to the active power sequence corresponding to each distribution line
P1 and active power sequence corresponding to each electric energy meter
The P2 determines the distribution line corresponding to the address of each electric energy meter, and comprises the following steps:
according to the formula dist: (
P1，
P2)= 
Calculating for each distribution line
P1 corresponding to all electric energy meters
Difference between P2, select dist (d:
P1，
p2) the address of the smallest electric energy meter corresponds to the current distribution line; wherein dist: (
P1，
P2) is
P1 and
the distance between P2, n is
P1 and
the number of power points in P2, i being
P1 and
sequence number of power points in P2.
Optionally, in the channel identification unit, according to the active power sequence corresponding to each distribution line
P1 and active power sequence corresponding to each electric energy meter
The P2 determines the distribution line corresponding to the address of each electric energy meter, and comprises the following steps:
the active power sequence corresponding to each distribution line
All power points in P1 are sequentially connected to form a first power curve, and the active power sequence corresponding to each electric energy meter is
All power points in P2 are sequentially connected to form a second power curve, and the first power curve corresponding to each distribution line is calculatedAnd selecting the address of the electric energy meter with the highest coincidence degree to correspond to the current distribution line.
Optionally, the electric quantity metering unit comprises a current transformer, a voltage transformer, a filter circuit, an AD conversion circuit and a controller, the current transformer and the voltage transformer are sequentially connected with the controller through the filter circuit and the AD conversion circuit, and the controller calculates the electric quantity according to electric signals output by the current transformer and the voltage transformer.
Optionally, the filter circuit includes a common-mode inductor L1, inductors L2 to L5, capacitors C1 to C3, and a differential amplifier U1;
the first pole of the output end of the current transformer or the voltage transformer is connected with the second pole through a capacitor C1, the first pole of the output end of the current transformer or the voltage transformer is further sequentially connected with the inverting end of a differential amplifier U1 through a first winding of a common-mode inductor L1, an inductor L2 and an inductor L3, the second pole is further sequentially connected with the inverting end of the differential amplifier U1 through a second winding of a common-mode inductor L1, an inductor L4 and an inductor L5, the common end of the inductor L2 and the inductor L3 is grounded through a capacitor C2, the common end of the inductor L4 and the inductor L5 is grounded through a capacitor C3, and the output end of the differential amplifier U1 is connected with an AD conversion circuit.
Optionally, the filter circuit further includes inverting amplifiers U2-U3, operational amplifiers U4-U5, resistors R1-R4 and capacitors C4-C7, the inverting amplifiers U2-U3, the operational amplifiers U4-U5, the resistors R1-R4 and the capacitors C4-C7 are connected between the output end of the differential amplifier U1 and the AD conversion circuit;
the output end of the differential amplifier U1 is connected with the inverting end of the inverting amplifier U2, the output end of the inverting amplifier U2 is connected with the inverting end of the inverting amplifier U3, the non-inverting end of the inverting amplifier U3 is grounded, and the output end of the inverting amplifier U3 is connected with the AD conversion circuit;
the output end of the inverting amplifier U3 is further grounded through a resistor R1 and a capacitor C4 in sequence, the common end of the resistor R1 and the capacitor C4 is connected with the in-phase end of the operational amplifier U4, the inverting end of the operational amplifier U4 is grounded through a resistor R2, the inverting end of the operational amplifier U4 is further connected with the output end of the operational amplifier U4 through a capacitor C5, the output end of the operational amplifier U4 is further grounded through a resistor R3 and a capacitor C6 in sequence, the common end of the resistor R3 and the capacitor C6 is connected with the in-phase end of the operational amplifier U5, the inverting end of the operational amplifier U5 is grounded through a resistor R4, the inverting end of the operational amplifier U5 is further connected with the output end of the operational amplifier U5 through a capacitor C7, and the output end of the operational amplifier U5 is further connected with the in-phase end.
Compared with the prior art, the multi-channel electric energy meter misalignment online monitoring device has the following beneficial effects:
(1) after the pairing relation between the electricity consumption in the electricity metering unit and the electricity consumption records of the electric energy meters is determined, the accuracy of the electricity metering unit is higher than that of all the electric energy meters, so that the metering accuracy of the electric energy meters can be evaluated by reading of the high-accuracy electricity metering unit, the inaccurate online monitoring of a plurality of electric energy meters can be simultaneously carried out, each unqualified electric energy meter can be identified, the qualified electric energy meters are prevented from being replaced, resources are saved, and the labor and logistics cost are reduced;
(2) the power distribution line corresponding to the address of each electric energy meter is determined according to the electric signal of each power distribution line and the electric quantity data of each electric energy meter, the corresponding relation does not need to be manually set, a worker does not need to know the power distribution line corresponding to each electric energy meter, and the misalignment detection of the electric energy meters is easy to realize;
(3) comparing the slopes of any adjacent power points on the same time period of the first power curve and the second power curve, and abandoning the current slope when the slope change is larger than expected, namely abandoning the slope change caused by pulse interference;
(4) respectively calculating active power sequence
P1 and active power sequence
Power increment between any two adjacent power points in P2Abandoning active power sequences
P1 and active power sequence
The power points corresponding to all the power increments in the P2 which are in accordance with normal distribution can eliminate measurement noise and power ripple noise interference caused by the working characteristics of electric appliances before active power sequence comparison, and further improve the accuracy of identifying the corresponding relation between the electric energy meter and the distribution line.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a block diagram of the structure of the misalignment online monitoring device of the multi-channel electric energy meter of the invention;
FIG. 2 is a power increment waveform of the active power sequence of the present invention;
fig. 3 is a block diagram of the electric quantity metering unit according to the present invention;
FIG. 4 is a circuit diagram of a conventional EMI filter circuit;
FIG. 5 is a circuit diagram of a filter circuit of the present invention;
FIG. 6 is a waveform diagram of insertion loss of the filter circuit of the present invention and a conventional EMI filter circuit.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
As shown in fig. 1, the device for online monitoring misalignment of a multi-channel electric energy meter of the present embodiment includes an electric quantity metering unit, an electric meter reading unit, a channel identification unit, and an error determination unit. The electric quantity metering unit is connected with each electric energy meter in series through different distribution lines respectively and is used for collecting electric signals flowing through each distribution line and calculating the electricity consumption according to the electric signals, and the precision of the electric quantity metering unit is higher than that of all the electric energy meters. The electric meter reading unit is respectively connected with each electric energy meter through different data buses and used for reading the address of each electric energy meter through the data buses by utilizing a bit reduction address method and obtaining the electricity utilization record of each electric energy meter according to the address of each electric energy meter. The channel identification unit is respectively connected with the electric quantity metering unit and the electric meter reading unit and used for acquiring the electric quantity data of each electric energy meter according to the address of each electric energy meter and determining the distribution lines corresponding to the addresses of each electric energy meter according to the electric signals of each distribution line and the electric quantity data of each electric energy meter. The error judgment unit is respectively connected with the electric quantity metering unit, the electric meter reading unit and the channel identification unit and used for calculating the metering accuracy of the electric energy meter corresponding to each distribution line according to the electric quantity and the electric record corresponding to each distribution line.
In this embodiment, each electric energy meter corresponds to one user, each electric energy meter has a unique address, the data bus can be an RS485 bus, and the electric meter reading unit can search for the address of each electric energy meter through the RS485 bus, so that the electricity consumption record of each electric energy meter can be read according to the address of each electric energy meter, the electricity consumption record is the electricity consumption of the user, and thus the address of each electric energy meter corresponds to the electricity consumption record of each electric energy meter one by one. The electric quantity metering unit is connected with each electric energy meter in series through different distribution lines respectively, and to the electric quantity metering unit and the electric energy meter connected with the same distribution line, because the user that the same distribution line corresponds is the same, the electric quantity metering unit calculates the power consumption that obtains on this distribution line and the reading of electric energy meter is unanimous basically, only has the difference of precision. If the device is connected with N electric energy meters at the same time, N lines of distribution lines exist, and the electric quantity metering unit can calculate N electric quantities and obtain N electric records. The power consumption in the power metering unit and the multi-path power distribution lines can be considered to have a known one-to-one correspondence relationship, so that the power consumption and the power distribution lines have a known one-to-one correspondence relationship, the addresses of the electric energy meter and the power consumption records have a known one-to-one correspondence relationship, and the correspondence relationship between the power distribution lines and the addresses of the electric energy meter is unknown. Because the electricity metering unit has a plurality of electricity consumptions, the corresponding relation between the electricity consumption and the electricity consumption record needs to be known before comparing the electricity consumption with the electricity consumption record, and the distribution line corresponding to the address of each electric energy meter is determined through the channel identification unit. After the pairing relation between the electricity consumption in the electricity metering unit and the electricity consumption records of the electric energy meters is determined, the accuracy of the electricity metering unit is higher than that of all the electric energy meters, so that the metering accuracy of the electric energy meters can be evaluated by reading of the high-accuracy electricity metering unit, the plurality of electric energy meters can be simultaneously monitored in an inaccurate online mode, each unqualified electric energy meter can be identified, the qualified electric energy meters are prevented from being replaced, resources are saved, and the labor and logistics cost are reduced.
In this embodiment, the channel recognition unit is used for confirming the distribution lines that the address of every electric energy meter corresponds, and for realizing this function, traditional practice is to set up the electric energy meter address that the distribution lines correspond through the RS485 bus and save to the device in, and the device utilizes the address of setting to read the power consumption record of electric energy meter through the communication interface protocol, compares with the power consumption that this distribution lines correspond and calculates. The pairing mode enables the electric energy meters to be replaced once, the electric energy meters need to be reset once, and field personnel must know the distribution lines corresponding to each electric energy meter, so that the realization is difficult.
In the preferred channel identification unit of this embodiment, determining the power distribution line corresponding to the address of each electric energy meter according to the electric signal of each power distribution line and the electric quantity data of each electric energy meter includes: the power acquisition module is used for acquiring a current instantaneous value and a voltage instantaneous value in the electric signal, calculating the active power P1 of the corresponding load of each distribution line according to the current instantaneous value and the voltage instantaneous value in the electric signal, and acquiring an active power sequence between sampling moments t 1-t 2
P1; acquiring a current instantaneous value and a voltage instantaneous value in the electric quantity data, calculating the active power P2 of the corresponding load of each electric energy meter according to the current instantaneous value and the voltage instantaneous value in the electric quantity data, and acquiring an active power sequence between sampling moments t 1-t 2
P2; according to the active power sequence corresponding to each distribution line
P1 and active power sequence corresponding to each electric energy meter
P2 identifies the power distribution line corresponding to the address of each power meter.
The electric signal or electric quantity data can represent the load characteristics of a user, including current instantaneous values, voltage instantaneous values, current harmonics, instantaneous admittance waveforms, instantaneous power waveforms, characteristic values, peak values and average values of current, root mean square values of current, high-frequency electromagnetic interference, voltage-current tracks, total harmonic distortion, active power and phases, and can also represent the characteristics of an electric quantity metering unit and an electric energy meter, including daily frozen electric quantity, state words, time, data acquisition time and the like. For the same line of distribution lines, the user load characteristics calculated by the electric quantity metering unit and the electric energy meter with the corresponding relationship or the characteristics of the electric quantity metering unit and the electric energy meter are closest to or even the same, so that the corresponding relationship between the distribution lines and the electric energy meter can be identified through characteristic comparison.
For the user load characteristics, the active power represents the specific size of the user load, and since any two user loads are unlikely to be the same basically, the active power in the same time period is unlikely to be the same, but the power consumption and the power consumption record in the same time period on the same circuit distribution line should be the closest, so that the active power calculated by the power metering unit and the electric energy meter in the same time period respectively should be the closest or even the same. In this embodiment, the channel identification unitAccording to the active power sequence corresponding to each distribution line
P1 and active power sequence corresponding to each electric energy meter
P2 determines the distribution line corresponding to the address of each electric energy meter, specifically calculates the closest active power sequence
Active power sequence of P1
P2. In principle, comparison can be performed only by sampling one power point at a single moment or a plurality of power points at a plurality of moments, in order to avoid the situation that identification is wrong due to the fact that the active power of two user loads is the same at a certain moment or a plurality of moments accidentally, the embodiment selects an active power sequence between the sampling moments t 1-t 2, wherein the active power sequence comprises a sufficient number of power points, and even if the active power of two user loads is the same at a certain moment or a plurality of moments accidentally, the power consumption and the power consumption record in the same time period on the same circuit distribution line are still the closest in view of the active power sequence as a whole. Therefore, the distribution line corresponding to the address of each electric energy meter is determined according to the electric signal of each distribution line and the electric quantity data of each electric energy meter, the corresponding relation does not need to be set manually, a worker does not need to know the distribution line corresponding to each electric energy meter, and misalignment detection of the electric energy meters is easy to achieve. Wherein the active power
P=
，
For the instantaneous value of the voltage to be,
for the current transient, n is the number of samples per cycle, and j is the number of samples.
The specific point, in the channel identification unit, is according to the corresponding active power sequence of each distribution line
P1 and active power sequence corresponding to each electric energy meter
The P2 determines the distribution line corresponding to the address of each electric energy meter, and comprises the following steps: according to the formula dist: (
P1，
P2)= 
Calculating for each distribution line
P1 corresponding to all electric energy meters
Difference between P2, select dist (d:
P1，
p2) the address of the smallest electric energy meter corresponds to the current distribution line; wherein dist: (
P1，
P2) is
P1 and
the distance between P2, n is
P1 and
the number of power points in P2, i being
P1 and
sequence number of power points in P2. Wherein, dist: (
P1, vP2) at the time of the last cycle
Electric energy meter corresponding to P2 and
the distribution line corresponding to P1 can be identified as corresponding.
The present embodiment can directly calculate the corresponding distribution line of each distribution line by the above formula
P1 corresponding to all electric energy meters
The difference between P2 is the distance of the active power sequence calculated on the whole, and the calculated amount for identifying the corresponding relation between the distribution line and the electric energy meter is the least and most direct, but a certain power point is caused by the impulse interference in the deviceSo large that a single power point affects the overall distance of the active power sequence, as if distribution line a corresponds
P1 (K1, K1, K1, K1), distribution line A corresponding to electric energy meter a
P2 (K1, 5K1, K1, K1), wherein 5K1 is pulsed interference. In the absence of pulse interference, the electric energy meter a corresponds to
P2 should be
P2 (K1, K1, K1, K1) for making distribution line A corresponding thereto
P1 corresponding to electric energy meter a
The P2 distance is at a minimum of zero, and the occurrence of the impulse disturbance 5K1 is greatly increased
P1 and
the distance P2 may cause distribution line A to correspond to
P1 corresponding to electric energy meter a
The P2 distance is not minimal, causing recognition errors.
To avoid the above accidental situation, in the preferred channel identification unit of this embodiment, the active power sequence corresponding to each distribution line is determined according to the active power sequence corresponding to each distribution line
P1 and active power sequence corresponding to each electric energy meter
The P2 determines the distribution line corresponding to the address of each electric energy meter, and comprises the following steps: the active power sequence corresponding to each distribution line
All power points in P1 are sequentially connected to form a first power curve, and the active power sequence corresponding to each electric energy meter is
And sequentially connecting all the power points in the P2 to form a second power curve, calculating the coincidence degree of the first power curve corresponding to each distribution line and the second power curves corresponding to all the electric energy meters, and selecting the address of the electric energy meter with the highest coincidence degree to correspond to the current distribution line. The calculation of the contact ratio is to compare the slopes of any adjacent power points on the same time period of the first power curve and the second power curve, and to discard the current slope when the slope change is larger than expected, namely to discard the slope change caused by the pulse interference.
In this embodiment, not only the pulse interference but also the power ripple noise caused by the voltage and measurement noise that fluctuate randomly on the distribution line and the operating characteristics of the electric appliance, which affect the active power, are present on the distribution line at the same time
P1 and
p2, power ripple noise pairs on the same line correspond to each other
P1 and
the same effect is caused by P2, and the effects can be mutually cancelled during identification without filtering processing. As shown in fig. 2, in the present embodiment, statistical tests are performed on a large amount of power ripple noise data caused by measurement noise, electrical appliance operating characteristics, and the like, and it is shown that the power increment of the ripple noise follows a normal distribution, and the average value thereof is approximately zero. In fig. 2, 5 peaks represent switching events sent by the electrical appliances of the user load, and the secondary peaks among the 5 peaks are power harmonic interference, so that a large number of secondary peaks among the 5 peaks satisfy normal distribution. Therefore, in the preferred channel identification unit of this embodiment, the determining, according to the electrical signal of each power distribution line and the electric quantity data of each electric energy meter, the power distribution line corresponding to the address of each electric energy meter further includes: respectively calculating active power sequence
P1 and active power sequence
Discarding the active power sequence at power increment between any two adjacent power points in P2
P1 and active power sequence
And power points corresponding to all power increments conforming to the normal distribution in P2. Therefore, measurement noise and power ripple noise interference caused by the working characteristics of the electric appliance can be eliminated before active power sequence comparison, and the accuracy of identifying the corresponding relation between the electric energy meter and the distribution line is further improved.
As shown in fig. 3, the electric quantity metering unit of this embodiment includes a current transformer, a voltage transformer, a filter circuit, an AD conversion circuit, and a controller, where the current transformer and the voltage transformer are sequentially connected to the controller through the filter circuit and the AD conversion circuit, and the controller calculates the electric quantity according to electric signals output by the current transformer and the voltage transformer. The current transformer and the voltage transformer are respectively used for acquiring a current instantaneous value and a voltage instantaneous value in an electric signal flowing through a distribution line, and a high signal of the distribution line can be used by a rear module only after being subjected to voltage reduction of the transformers; the filter circuit can play a two-way anti-interference role, on one hand, external electromagnetic interference introduced from the signal line is filtered, on the other hand, the filter circuit can also avoid the device per se from emitting noise interference to the outside so as to avoid influencing the normal work of other electronic devices, and the filter circuit plays a role in inhibiting differential mode and common mode interference. In practice, hardware circuits of the electric energy meter have similar structures to the electric quantity metering unit of the embodiment, the precision of each part of the circuit is not high, and in order to realize that the precision of the electric quantity metering unit is higher than that of the electric energy meter, the embodiment mainly improves the filter circuit so as to improve the precision of the electric quantity metering unit.
As shown in fig. 4, the insertion loss is an important index for evaluating the EMI filter circuit, and the interference suppression capability of the EMI filter circuit is also measured by the insertion loss. The insertion loss is defined as the ratio of the power delivered to the load from the noise source when the EMI filter circuit is not engaged to the power delivered to the load from the noise source after the EMI filter circuit is engaged. Therefore, the stronger the insertion loss, the better the filtering effect of the EMI filter circuit. The present embodiment provides a filter circuit, as shown in fig. 5, including a common mode inductor L1, inductors L2 to L5, capacitors C1 to C3, and a differential amplifier U1. The first pole of the output end of the current transformer or the voltage transformer is connected with the second pole through a capacitor C1, the first pole of the output end of the current transformer or the voltage transformer is further sequentially connected with the inverting end of a differential amplifier U1 through a first winding of a common-mode inductor L1, an inductor L2 and an inductor L3, the second pole is further sequentially connected with the inverting end of the differential amplifier U1 through a second winding of a common-mode inductor L1, an inductor L4 and an inductor L5, the common end of the inductor L2 and the inductor L3 is grounded through a capacitor C2, the common end of the inductor L4 and the inductor L5 is grounded through a capacitor C3, and the output end of the differential amplifier U1 is connected with an AD conversion circuit. In this embodiment, C1 is a differential mode noise suppression capacitor, L1, C2 and C3 form a common mode noise removal circuit, L1 winds two windings with the same number of turns and opposite directions around the same iron core, and the magnetic fluxes generated in the iron core by the alternating current input back-and-forth current are opposite in directions and cancel each other out, so that high impedance is presented to the common mode noise between the power phase line and the ground line, and a good suppression effect is provided for the common mode noise. L2, L3 and C2 constitute a T-type network, and L4, L5 and C3 constitute a T-type network. As a result of simulation of the insertion loss of the circuits of fig. 4 and 5, fig. 6 shows that curve "1" in fig. 6 represents the insertion loss of the circuit of fig. 4, and curve "2" represents the insertion loss of the circuit of fig. 5. As can be seen from fig. 6, the insertion loss of the circuit of fig. 5 is much better than that of the conventional EMI filter circuit, and is more obvious at high frequency and better in filtering performance after the resonance point.
In this embodiment, the differential amplifier U1 is configured to convert the differential signal after the EMI filtering into a single-ended signal and output the single-ended signal, and further suppress common mode interference in the circuit, and the differential amplifier U1 is formed by an operational amplifier. When the input signal of the operational amplifier is zero, the output is also completely zero, which is the state of an ideal operational amplifier. However, in an actual operational amplifier, due to elements, processes and the like, errors are generated, when an input is zero, an output end is not zero, and a voltage appearing at the output end is called an output bias voltage. The case where the bias voltage varies with temperature, time, and the like is called zero shift, which is an important property to express the characteristics of the operational amplifier. In this embodiment, how to suppress the offset and the drift introduced by the differential amplifier U1 is a non-negligible problem, from the output end of the current or voltage transformer to the input end of the AD conversion circuit, the operational amplifier is used in the transmission and processing links of the signal, and the offset voltage and the drift generated by the previous stage of operational amplifier will be accumulated in the next stage of operational amplifier, so as to affect the acquisition accuracy of the electricity metering unit. Since the bias voltage of the op-amp changes very slowly with temperature, it can be eliminated from the useful signal according to this feature. Therefore, as shown in FIG. 5, the filter circuit of the present embodiment further includes inverting amplifiers U2-U3, operational amplifiers U4-U5, resistors R1-R4 and capacitors C4-C7, and inverting amplifiers U2-U3, operational amplifiers U4-U5, resistors R1-R4 and capacitors C4-C7 are connected between the output terminal of the differential amplifier U1 and the AD conversion circuit. The output end of the differential amplifier U1 is connected with the inverting end of the inverting amplifier U2, the output end of the inverting amplifier U2 is connected with the inverting end of the inverting amplifier U3, the non-inverting end of the inverting amplifier U3 is grounded, and the output end of the inverting amplifier U3 is connected with the AD conversion circuit. The output end of the inverting amplifier U3 is further grounded through a resistor R1 and a capacitor C4 in sequence, the common end of the resistor R1 and the capacitor C4 is connected with the in-phase end of the operational amplifier U4, the inverting end of the operational amplifier U4 is grounded through a resistor R2, the inverting end of the operational amplifier U4 is further connected with the output end of the operational amplifier U4 through a capacitor C5, the output end of the operational amplifier U4 is further grounded through a resistor R3 and a capacitor C6 in sequence, the common end of the resistor R3 and the capacitor C6 is connected with the in-phase end of the operational amplifier U5, the inverting end of the operational amplifier U5 is grounded through a resistor R4, the inverting end of the operational amplifier U5 is further connected with the output end of the operational amplifier U5 through a capacitor C7, and the output end of the operational amplifier U5 is further connected with the in-phase end.
In this embodiment, the inverting amplifiers U2 and U3 form two-stage inverters connected in series, so that the amplitude and phase of the output signal are the same as those of the input signal, the resistors R1 to R2, the capacitors C4 to C5 and the operational amplifier U4 form a first-stage integrating circuit, the resistors R3 to R4, the capacitors C6 to C6 and the operational amplifier U5 form a second-stage integrating circuit, and the two-stage integrating circuits are connected in series, so that the integration constant is large, and the direct current component in the signal can be separated and fed back to the input end, thereby suppressing the direct current bias voltage in the original signal. The frequency domain expression of each stage of the integrating circuit is as follows:
the transfer function expression denominator of the two-stage integrator circuit is composed of
One, have better low frequency and pass, the characteristic of high frequency cut-off, can better restrain the low frequency temperature drift, and reduce the attenuation to the useful signal. Capacitor in circuitThe resistance values are empirically selected, C4= C6=1 μ F, C5= C7=0.1 μ F, R1= R3=1M Ω, and R2= R4=1.1M Ω, when the cutoff frequency is about 1 Hz. The circuit has good inhibition to the bias voltage and the temperature drift of the differential amplifier U1, the attenuation effect is obvious, and under the normal working frequency, the amplitude and the phase are not influenced, so that the direct current noise caused by the maladjustment of the output voltage or the temperature drift of the differential amplifier U1 can be eliminated.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (8)
1. A multi-channel electric energy meter misalignment online monitoring device is characterized by comprising an electric quantity metering unit, an electric meter reading unit, a channel identification unit and an error judgment unit;
the electric quantity metering unit is connected with each electric energy meter in series through different distribution lines respectively and is used for collecting electric signals flowing through each distribution line and calculating the electricity consumption according to the electric signals, and the precision of the electric quantity metering unit is higher than that of all the electric energy meters;
the electric meter reading unit is respectively connected with each electric energy meter through different data buses and is used for reading the address of each electric energy meter through the data buses by utilizing a bit reduction address method and acquiring the electricity utilization record of each electric energy meter according to the address of each electric energy meter;
the channel identification unit is respectively connected with the electric quantity metering unit and the electric meter reading unit and is used for acquiring the electric quantity data of each electric energy meter according to the address of each electric energy meter and determining the distribution lines corresponding to the addresses of each electric energy meter according to the electric signals of each distribution line and the electric quantity data of each electric energy meter;
the error judgment unit is respectively connected with the electric quantity metering unit, the electric meter reading unit and the channel identification unit and used for calculating the metering accuracy of the electric energy meter corresponding to each distribution line according to the electric quantity and the electric record corresponding to each distribution line.
2. The device for online misalignment monitoring of multi-channel electric energy meters according to claim 1, wherein in the channel identification unit, the electric power distribution line corresponding to the address of each electric energy meter is determined according to the electric signal of each electric power distribution line and the electric quantity data of each electric energy meter, including;
acquiring a current instantaneous value and a voltage instantaneous value in the electric signal, calculating the active power P1 of the corresponding load of each distribution line according to the current instantaneous value and the voltage instantaneous value in the electric signal, and acquiring an active power sequence between sampling moments t 1-t 2
P1；
Acquiring a current instantaneous value and a voltage instantaneous value in the electric quantity data, calculating the active power P2 of the corresponding load of each electric energy meter according to the current instantaneous value and the voltage instantaneous value in the electric quantity data, and acquiring an active power sequence between sampling moments t 1-t 2
P2；
According to the active power sequence corresponding to each distribution line
P1 and active power sequence corresponding to each electric energy meter
P2 identifies the power distribution line corresponding to the address of each power meter.
3. The on-line misalignment monitoring device for multi-channel electric energy meters as claimed in claim 2, wherein the channel identification unit determines the corresponding power distribution line of each electric energy meter according to the electric signal of each power distribution line and the electric quantity data of each electric energy meter, and further comprises:
respectively calculating active power sequence
P1 and active power sequence
Discarding the active power sequence at power increment between any two adjacent power points in P2
P1 and active power sequence
And power points corresponding to all power increments conforming to the normal distribution in P2.
4. The multi-channel electric energy meter misalignment on-line monitoring device as claimed in claim 2, wherein in the channel identification unit, the active power sequence corresponding to each distribution line is determined according to the active power sequence corresponding to each distribution line
P1 and active power sequence corresponding to each electric energy meter
The P2 determines the distribution line corresponding to the address of each electric energy meter, and comprises the following steps:
according to the formula dist: (
P1，
P2)=
Calculating for each distribution line
P1 corresponding to all electric energy meters
Difference between P2, select dist (d:
p1, vP2) the address of the smallest electric energy meter corresponds to the current distribution line; wherein dist: (
P1，
P2) is
P1 and
the distance between P2, n is
P1 and
the number of power points in P2, i being
P1 and
sequence number of power points in P2.
5. The device for online misalignment monitoring of multi-channel electric energy meters as claimed in claim 2, wherein the channel identification unit is configured to identify the active power sequence P1 corresponding to each distribution line and the active power sequence corresponding to each electric energy meter
P2Determining a distribution line corresponding to the address of each electric energy meter, wherein the distribution line comprises:
the active power sequence corresponding to each distribution line
All power points in P1 are sequentially connected to form a first power curve, and the active power sequence corresponding to each electric energy meter is
And sequentially connecting all the power points in the P2 to form a second power curve, calculating the coincidence degree of the first power curve corresponding to each distribution line and the second power curves corresponding to all the electric energy meters, and selecting the address of the electric energy meter with the highest coincidence degree to correspond to the current distribution line.
6. The device for online monitoring the misalignment of the multi-channel electric energy meter as claimed in claim 1, wherein the electric quantity metering unit comprises a current transformer, a voltage transformer, a filter circuit, an AD conversion circuit and a controller, the current transformer and the voltage transformer are sequentially connected with the controller through the filter circuit and the AD conversion circuit, and the controller calculates the electric quantity according to the electric signals output by the current transformer and the voltage transformer.
7. The on-line misalignment monitoring device for the multi-channel electric energy meter as claimed in claim 6, wherein the filter circuit comprises a common-mode inductor L1, inductors L2-L5, capacitors C1-C3 and a differential amplifier U1;
the first pole of the output end of the current transformer or the voltage transformer is connected with the second pole through a capacitor C1, the first pole of the output end of the current transformer or the voltage transformer is further sequentially connected with the inverting end of a differential amplifier U1 through a first winding of a common-mode inductor L1, an inductor L2 and an inductor L3, the second pole is further sequentially connected with the inverting end of the differential amplifier U1 through a second winding of a common-mode inductor L1, an inductor L4 and an inductor L5, the common end of the inductor L2 and the inductor L3 is grounded through a capacitor C2, the common end of the inductor L4 and the inductor L5 is grounded through a capacitor C3, and the output end of the differential amplifier U1 is connected with an AD conversion circuit.
8. The multi-channel electric energy meter misalignment online monitoring device as claimed in claim 7, wherein the filter circuit further comprises inverting amplifiers U2-U3, operational amplifiers U4-U5, resistors R1-R4 and capacitors C4-C7, the inverting amplifiers U2-U3, the operational amplifiers U4-U5, the resistors R1-R4 and the capacitors C4-C7 are connected between the output end of the differential amplifier U1 and the AD conversion circuit;
the output end of the differential amplifier U1 is connected with the inverting end of the inverting amplifier U2, the output end of the inverting amplifier U2 is connected with the inverting end of the inverting amplifier U3, the non-inverting end of the inverting amplifier U3 is grounded, and the output end of the inverting amplifier U3 is connected with the AD conversion circuit;
the output end of the inverting amplifier U3 is further grounded through a resistor R1 and a capacitor C4 in sequence, the common end of the resistor R1 and the capacitor C4 is connected with the in-phase end of the operational amplifier U4, the inverting end of the operational amplifier U4 is grounded through a resistor R2, the inverting end of the operational amplifier U4 is further connected with the output end of the operational amplifier U4 through a capacitor C5, the output end of the operational amplifier U4 is further grounded through a resistor R3 and a capacitor C6 in sequence, the common end of the resistor R3 and the capacitor C6 is connected with the in-phase end of the operational amplifier U5, the inverting end of the operational amplifier U5 is grounded through a resistor R4, the inverting end of the operational amplifier U5 is further connected with the output end of the operational amplifier U5 through a capacitor C7, and the output end of the operational amplifier U5 is further connected with the in-phase end.
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Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2400310A2 (en) * | 2010-06-22 | 2011-12-28 | General Electric Company | Method and system for indicating faults in an electricity meter |
| CN103985236A (en) * | 2014-05-08 | 2014-08-13 | 国家电网公司 | Automatic meter reading system of electric energy meter |
| CN104569902A (en) * | 2014-11-21 | 2015-04-29 | 国家电网公司 | Digital type electric energy meter power consumption measuring device and method |
| CN105911505A (en) * | 2016-04-12 | 2016-08-31 | 广东工业大学 | Smart meter testing method |
| CN109471059A (en) * | 2018-10-15 | 2019-03-15 | 广州云新信息技术有限公司 | A kind of ammeter automatic tour inspection system and method |
| CN110244253A (en) * | 2019-06-05 | 2019-09-17 | 辽宁省电能计量器具检定站有限公司 | Provincial measurement centre's standard volume passes online management-control method |
| CN110515027A (en) * | 2019-08-14 | 2019-11-29 | 国网湖北省电力有限公司武汉供电公司 | A kind of non-one key electric energy meter of formula of registering one's residence is visited one house after another Check System and method |
| CN110879377A (en) * | 2019-11-22 | 2020-03-13 | 国网新疆电力有限公司电力科学研究院 | Metering device fault tracing method based on deep belief network |
| CN111398883A (en) * | 2020-02-28 | 2020-07-10 | 国网湖南省电力有限公司 | Electric energy meter truncation error online evaluation method, system and medium |
| CN112034411A (en) * | 2020-07-20 | 2020-12-04 | 中国电力科学研究院有限公司 | Intelligent isolation switch equipment and electric energy meter running state analysis method |
| CN112034412A (en) * | 2020-07-20 | 2020-12-04 | 中国电力科学研究院有限公司 | Intelligent electric energy meter misalignment analysis method and system based on intelligent isolating switch |
-
2020
- 2020-12-24 CN CN202011545040.6A patent/CN112285638B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2400310A2 (en) * | 2010-06-22 | 2011-12-28 | General Electric Company | Method and system for indicating faults in an electricity meter |
| CN103985236A (en) * | 2014-05-08 | 2014-08-13 | 国家电网公司 | Automatic meter reading system of electric energy meter |
| CN104569902A (en) * | 2014-11-21 | 2015-04-29 | 国家电网公司 | Digital type electric energy meter power consumption measuring device and method |
| CN105911505A (en) * | 2016-04-12 | 2016-08-31 | 广东工业大学 | Smart meter testing method |
| CN109471059A (en) * | 2018-10-15 | 2019-03-15 | 广州云新信息技术有限公司 | A kind of ammeter automatic tour inspection system and method |
| CN110244253A (en) * | 2019-06-05 | 2019-09-17 | 辽宁省电能计量器具检定站有限公司 | Provincial measurement centre's standard volume passes online management-control method |
| CN110515027A (en) * | 2019-08-14 | 2019-11-29 | 国网湖北省电力有限公司武汉供电公司 | A kind of non-one key electric energy meter of formula of registering one's residence is visited one house after another Check System and method |
| CN110879377A (en) * | 2019-11-22 | 2020-03-13 | 国网新疆电力有限公司电力科学研究院 | Metering device fault tracing method based on deep belief network |
| CN111398883A (en) * | 2020-02-28 | 2020-07-10 | 国网湖南省电力有限公司 | Electric energy meter truncation error online evaluation method, system and medium |
| CN112034411A (en) * | 2020-07-20 | 2020-12-04 | 中国电力科学研究院有限公司 | Intelligent isolation switch equipment and electric energy meter running state analysis method |
| CN112034412A (en) * | 2020-07-20 | 2020-12-04 | 中国电力科学研究院有限公司 | Intelligent electric energy meter misalignment analysis method and system based on intelligent isolating switch |
Non-Patent Citations (2)
| Title |
|---|
| 唐登平 等: "基于IEC61850标准的数字化电能表检测技术研究", 《国外电子测量技术》 * |
| 徐宏伟 等: "一种含噪声测试的数字化电能表计量性能检测系统", 《国外电子测量技术》 * |
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