CN-122017706-A - Efficient electric measuring instrument verification system and verification method

CN122017706ACN 122017706 ACN122017706 ACN 122017706ACN-122017706-A

Abstract

The application relates to the technical field of electric power metering test, and discloses a high-efficiency electric measuring instrument verification system and a verification method, wherein the system comprises a central control unit and a central low-power consumption reference source which are positioned in a primary potential domain, and a plurality of distributed active servo nodes positioned in a secondary floating potential domain, wherein each node is connected through a virtual floating bus, the differential error amplifying unit compares the signal with an analog standard reference signal transmitted through the fluxgate isolation to generate an instruction to control the power converting unit to actively compensate the line voltage drop. The application realizes zero-voltage drop high-precision transmission of verification signals through the distributed floating architecture and the terminal closed-loop feedback, effectively inhibits common-mode interference, and has the functions of dynamic topology reconstruction and energy feedback.

Inventors

Geng Ruishuang
JIN RI
ZHOU XINGCHEN
ZHANG JINGYAN

Assignees

国能大渡河检修安装有限公司

Dates

Publication Date: 20260512
Application Date: 20260114

Claims (10)

1. The efficient electric measuring instrument verification system is characterized by comprising a central control unit, a central low-power consumption reference source, a virtual floating bus and a plurality of distributed active servo nodes; the central control unit and the central low-power consumption reference source are positioned in a primary potential domain, and the primary potential domain takes a ground protection ground wire as a reference potential; the distributed active servo nodes respectively form independent secondary floating potential domains, and the output end of each distributed active servo node is connected to an input binding post of the tested electric measuring instrument; The virtual floating ground bus is connected between the primary potential domain and the secondary floating ground potential domain and is used for transmitting electric energy, control signals and analog standard reference signals; the central control unit sends a phase configuration instruction and an amplitude control instruction to the distributed active servo nodes through the virtual floating bus; and the distributed active servo nodes output driving voltages to the tested electric measuring instrument according to the analog standard reference signals.
2. The efficient electrical meter verification system of claim 1, wherein each of the distributed active servo nodes has integrated therein a four-quadrant power conversion unit, a differential error amplification unit, an embedded kelvin sensing circuit, and a rectifying and voltage stabilizing circuit; the rectification voltage stabilizing circuit receives alternating current energy from the virtual floating ground bus and generates a direct current power supply, a direct current output negative electrode of the rectification voltage stabilizing circuit is defined as floating signal ground, and the secondary floating ground potential domain takes the floating signal ground as a reference potential; The embedded Kelvin sensing circuit is connected to an input binding post of the tested electric measuring instrument and used for collecting a terminal voltage feedback signal; the first input end of the differential error amplifying unit receives the analog standard reference signal, the second input end of the differential error amplifying unit receives the terminal voltage feedback signal, and the differential error amplifying unit outputs a voltage correction command signal according to the difference value between the analog standard reference signal and the terminal voltage feedback signal; and the four-quadrant power conversion unit adjusts the amplitude and the phase of the driving voltage according to the voltage correction command signal.
3. The efficient electrical meter verification system of claim 2, further comprising an electrically isolated connection assembly disposed between the primary potential domain and the secondary floating potential domain; The electrical isolation connection assembly comprises a high-frequency isolation transformer and a fluxgate isolation interface; The high-frequency isolation transformer is used for coupling power energy on the virtual floating ground bus to the rectifying and voltage stabilizing circuit and blocking a direct-current conductive path between the primary potential domain and the secondary floating ground potential domain; The fluxgate isolation interface is connected between the central low-power consumption reference source and the differential error amplification unit and is used for linearly transmitting the analog standard reference signal from the primary potential domain to the secondary floating potential domain; The fluxgate isolation interface internally comprises a closed-loop control circuit and a secondary compensation winding, and transmission precision is maintained through a zero-flux feedback mechanism.
4. The system of claim 2, wherein the virtual floating bus comprises an energy feedback dc bus; the direct current input ends of the four-quadrant power conversion units inside the distributed active servo nodes are all connected in parallel to the energy feedback direct current bus; The direct current input end of each four-quadrant power conversion unit is connected with a local energy storage capacitor in parallel; when the distributed active servo node is in a source mode operation, the full-bridge inverter circuit acquires electric energy from the energy feedback direct current bus; When the distributed active servo nodes are in a load mode operation, the full-bridge inverter circuit rectifies electric energy fed back by the tested electric measuring instrument and then injects the rectified electric energy into the energy feedback direct current bus for other distributed active servo nodes in a source mode operation.
5. The efficient electrical meter verification system of claim 2, wherein the embedded kelvin sensing circuit includes a four-wire connection port and a high input impedance meter amplifier; the four-wire system connection port comprises two power driving circuits and two voltage sensing circuits; The two power driving circuits are connected between the alternating current output end of the four-quadrant power conversion unit and the input binding post of the tested electric measuring instrument and used for transmitting load current; The two voltage sensing lines are connected between an input terminal of the tested electric measuring instrument and an input end of the high input impedance instrument amplifier, and the two voltage sensing lines do not bear load current; the high input impedance instrumentation amplifier outputs the terminal voltage feedback signal to the differential error amplification unit.
6. The high efficiency electrical meter verification system of claim 5, wherein the distributed active servo node is configured to perform zero-voltage-drop servo control; The differential error amplifying unit is internally integrated with a proportional-integral-differential controller; The differential error amplifying unit calculates an instantaneous error signal of the analog standard reference signal and the terminal voltage feedback signal; the proportional-integral-derivative controller adjusts the voltage correction command signal according to the instantaneous error signal and controls the four-quadrant power conversion unit to increase the amplitude of the driving voltage; The amplitude of the driving voltage rise is equal to the voltage drop of the load current on the line impedance of the two power driving lines, so that the actual potential at the input binding post of the tested electric measuring instrument is consistent with the analog standard reference signal.
7. The efficient electrical meter verification system of claim 2, wherein the distributed active servo node is further configured to perform an impedance resolution and parameter tuning procedure prior to verification runs; The four-quadrant power conversion unit injects a linear frequency modulation pulse voltage signal into the tested electric measuring instrument; The distributed active servo node acquires an instantaneous terminal voltage response signal sequence and an instantaneous loop current response signal sequence of the tested electric measuring instrument and converts the instantaneous terminal voltage response signal sequence and the instantaneous loop current response signal sequence into a frequency domain voltage sequence and a frequency domain current sequence; the distributed active servo node calculates complex input impedance according to the ratio of the frequency domain voltage sequence to the frequency domain current sequence, and calculates control loop phase margin of the differential error amplifying unit according to the complex input impedance; When the phase margin is less than a preset stability threshold and the complex input impedance exhibits capacitive loading characteristics, the distributed active servo node reduces the scaling factor of the differential error amplification unit internal controller and increases the differential factor.
8. The efficient electrical meter verification system of claim 1, wherein the central control unit has a topology configuration table stored therein, the central control unit configured to execute dynamic topology reconfiguration logic; The central control unit establishes a mapping relation between the physical address of the distributed active servo node and the logic node according to the wiring system parameters of the tested electric measuring instrument; When the wiring system parameter is a three-phase four-wire wiring mode, the central control unit controls the three distributed active servo nodes to respectively output voltage signals with 120-degree phase difference; when the wiring system parameter is a three-phase three-wire wiring mode, the central control unit controls one of the distributed active servo nodes to enter a zero potential reference mode, clamps the output end potential of the distributed active servo node to the reference potential of the secondary floating potential domain as a common reference point, and controls the other two distributed active servo nodes to output line voltage signals relative to the common reference point.
9. The efficient electrical meter verification system of claim 2, wherein there is no direct electrical connection between the floating signal ground and the earth guard ground; the direct current output anode of the rectifying and voltage stabilizing circuit is connected to the power input end of the four-quadrant power conversion unit, the differential error amplification unit and the embedded Kelvin sensing circuit; One end of a precision sampling resistor in the embedded Kelvin sensing circuit is connected to the floating signal ground, and a signal reference end of the differential error amplifying unit is connected to the floating signal ground.
10. A method of calibrating a highly efficient electrical meter calibration system according to any of claims 1-9, comprising the steps of: S100, the central control unit configures phase relation and operation modes of a plurality of distributed active servo nodes according to wiring system parameters of the tested electric measuring instrument; S200, a central low-power consumption reference source generates an analog standard reference signal, and the analog standard reference signal is transmitted to a differential error amplifying unit of a distributed active servo node through a fluxgate isolation interface; s300, an embedded Kelvin sensing circuit in the distributed active servo node collects a terminal voltage feedback signal at an input terminal of a tested electric measuring instrument through a voltage sensing circuit; s400, the differential error amplifying unit calculates the difference value between the analog standard reference signal and the terminal voltage feedback signal, and generates a voltage correction command signal by using a proportional-integral-derivative controller; And S500, the four-quadrant power conversion unit outputs a driving voltage according to the voltage correction command signal, and the voltage drop generated by the power driving circuit in the process of transmitting the driving voltage to the tested electric measuring instrument is automatically compensated, so that the actual potential at the input binding post of the tested electric measuring instrument tracks the analog standard reference signal.

Description

Efficient electric measuring instrument verification system and verification method Technical Field The invention relates to the technical field of electric power metering test, in particular to a high-efficiency electric measuring instrument verification system and a verification method. Background Along with the promotion of smart power grids construction, higher requirements are put forward on the output precision, stability and field adaptability of a signal source by verification operation of an electric measuring instrument. The existing electric measuring instrument calibrating device generally adopts a centralized signal source architecture, generates voltage and current signals through a power amplifier, and transmits the signals to a measured instrument by utilizing a test wire. In the practical verification process, a long connection line is often required between the power signal source and the measured instrument. Because of the inherent physical impedance of the test wire itself, the line impedance can create a voltage drop when transmitting high current or high frequency signals. This line drop results in the actual voltage applied to the input of the meter under test being lower than the set output value of the signal source. Although some conventional devices attempt to correct errors by presetting fixed compensation parameters through software, because the changes of the on-site wiring length, the contact resistance and the ambient temperature have uncertainty, the fixed compensation mode is difficult to eliminate the dynamically changed line voltage drop in real time, thereby affecting the accuracy of the electric energy metering verification. The output channels of conventional assay devices typically employ a common ground design or non-fully isolated architecture, with the reference potentials of the channels being coupled to each other through a ground or common backplane. When the electromagnetic environment is complex and the industrial site is inspected, the architecture is easy to form a ground loop, and common-mode interference signals are introduced, so that the measured signals are distorted. Meanwhile, when multiple meters with different potential reference points are involved in concurrent test, the lack of independent floating isolation potential fields easily causes electrical short circuits between channels, so that the reliability of test data is affected, and hardware damage to verification equipment and the tested meters is also likely to occur. When the existing device is used for coping with verification tasks of different wiring modes such as three-phase four-wire, three-phase three-wire and the like, hardware topology is often solidified. Operators often need to adjust the phase relationship by switching a complex relay matrix or manually changing wiring, and the operation process is tedious and has low efficiency. Meanwhile, the traditional power source mostly adopts a linear amplifying circuit, and when nonlinear loads such as inductive or capacitive loads are driven, reactive power fed back by the loads cannot be effectively recovered and can only be dissipated in a heat energy mode. This not only results in higher overall power consumption of the system and low energy utilization, but also increases the heat dissipation burden and volume of the device. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a high-efficiency electric measuring instrument verification system and a verification method, which solve the technical problems of large line voltage drop loss, poor common mode interference suppression capability and insufficient multi-phase topology configuration flexibility of the traditional electric measuring instrument verification device in long-distance transmission. In order to achieve the above purpose, the invention is realized by the following technical scheme: The first aspect of the invention provides a high-efficiency electrical measuring instrument verification system which mainly comprises a central control unit, a central low-power consumption reference source, a virtual floating bus and a plurality of distributed active servo nodes. In the system architecture, the central control unit and the central low-power reference source are located in a primary potential domain, and the primary potential domain takes the ground protection ground wire as a reference potential. The distributed active servo nodes are physically independent of each other and form independent secondary floating potential domains. The virtual floating ground bus is connected between the primary potential domain and the secondary floating ground domain and is used for transmitting electric energy, interacting control signals and transmitting analog standard reference signals. In this system, the output of each distributed active servo node is directly connected to the input terminal of the electrical meter under test. The central control uni