FIG. 5 is a structural diagram of another electrical parameter measurement and calculation apparatus according to an embodiment of the invention. As shown in FIG. 5, the electrical parameter measurement and calculation apparatus comprises a voltage acquisition module, a wireless module, an analog-to-digital conversion module and an electrical parameter calculation module. The wireless module comprises a wireless transmission unit and a wireless synchronization unit. In the embodiment shown in FIG. 5, the wireless transmission unit receives a current signal from the wireless current sensor in a wireless manner and transmits the current signal to the electrical parameter calculation module; the voltage acquisition module acquires a voltage signal and transmits the voltage signal to the analog-to-digital conversion module, and the analog-to-digital conversion module receives a time signal of the wireless synchronization unit, converts an analog voltage signal into a digital voltage signal under synchronous signal sampling information, and sends the digital voltage signal to the electrical parameter calculation module; and the electrical parameter calculation module calculates electrical parameter information according to the received current signal and voltage signal.

In the embodiment shown in FIG. 5, the wireless transmission unit receives the current signal in a wireless manner through Bluetooth, 2G, 3G, 4G, 5G, WIFI, sub1G, ZigBee or a custom wireless transmission protocol.

In the embodiment shown in FIG. 5, the wireless synchronization unit ensures signal sampling time synchronization of the current signal and the voltage signal by GNSS timing; 5G timing; sending local clock information to an opposite wireless transmission unit by the wireless transmission unit; or receiving local clock information from an opposite wireless transmission unit by the wireless transmission unit.

Considering the varying requirements for the layout of test wires during voltage and current acquisition processes, voltages across different positions of a line may be different in the case of acquisition of multiple voltages, due to the voltage drop of the line. Therefore, during voltage acquisition, it is optimal to acquire multiple voltages at positions as close as possible to a measured object; however, in the case of current acquisition from multiple lines, acquisition points can be farther apart since the same current flows through the same transmission line. Based on this consideration, the electrical parameter measurement and calculation system shown in FIG. 1 of the invention is equipped with the wireless current sensor, the acquired current signal is sent to the electrical parameter measurement and calculation apparatus through the wireless module, the electrical parameter measurement and calculation apparatus is provided with the voltage acquisition module, and a voltage of a nearest position of the measured object is directly measured through a test wire of the voltage acquisition module, so it is not necessary to send the acquired voltage signal in a wireless manner like the wireless current sensor. In this way, due to the characteristics of voltage acquisition, the tangling of test wires will not occur at this end of the electrical parameter measurement and calculation apparatus. In addition, because the electrical parameter measurement and calculation apparatus is provided with the voltage acquisition module, instead of a wireless voltage acquisition module, it is not necessary to equip the voltage acquisition module with a wireless module, nor is it necessary to equip the electrical parameter measurement and calculation apparatus with a wireless module corresponding to the voltage acquisition module, thus greatly reducing the use of wireless modules and reducing the communication data volume between devices and the requirement for synchronization between devices.

As mentioned above, in the embodiments shown in FIGS. 2-5, the wireless current sensor and the electrical parameter measurement and calculation apparatus realize the sampling time synchronization of the voltage signal and the current signal through the wireless module or wireless synchronization unit. In one embodiment, the wireless modules or wireless synchronization units of the wireless current sensor and the electrical parameter measurement and calculation apparatus can accurately realize the sampling time synchronization of the voltage signal and the current signal after obtaining standard time information by using timing devices, such as GNSS and 5G modules. In another embodiment, the wireless module or wireless synchronization unit of the wireless current sensor or the electrical parameter measurement and calculation apparatus adopts a wireless radio frequency module (for example, by means of Bluetooth, 2G, 3G, 4G, 5G, WIFI, sub1G, ZigBee or a custom wireless transmission protocol) to send time information of a local clock to the opposite wireless module or wireless synchronization unit, and then accurately realize the signal sampling time synchronization through corresponding algorithms, or receive the local clock information from the opposite wireless module or wireless synchronization unit to realize the signal sampling time synchronization. The wireless module or wireless synchronization unit adopted features small jitters (such as within 10 μs) and small time delays. The local clock information can be in the form of a series of pulses and/or timestamps. These pulses can directly control the sampling of the analog-to-digital conversion module or control the sampling of the analog-to-digital conversion module after computational processing. For example, when the pulse frequency of wireless transmission and reception is lower than the pulse frequency of actual sampling, the computational processing comprises frequency doubling. The time stamp can express more information about the local clock. For example, the time stamp may contain specific time information, such as date, hour, minute and second, or some agreed numerical serial number, which represents relative time, so as to achieve correct clock synchronization with the opposite end. The time error between the clock information received and restored by the wireless module or wireless synchronization unit of the wireless current sensor and the local clock information sent by the wireless module or wireless synchronization unit of the electrical parameter measurement and calculation apparatus should not exceed 20 μs, or the time error between the clock information received and restored by the wireless module or wireless synchronization unit of the electrical parameter measurement and calculation apparatus and the local clock information sent by the wireless module or wireless synchronization unit of the wireless current sensor should not exceed 20 μs. In this way, the wireless current sensor and the analog-to-digital conversion module of the electrical parameter measurement and calculation apparatus synchronously sample the respective signals at equal intervals, to realize the synchronization of voltage and current signals, thus ensuring the accuracy of electrical parameter calculation, for example, the measurement accuracy of power and/or electric energy is over 2%.

In the embodiments shown in FIGS. 2-5, the wireless current sensor and the electrical parameter measurement and calculation apparatus realize the sending and receiving of the current signal through the wireless module or wireless transmission unit, and the wireless module or wireless transmission unit can realize wireless transmission through Bluetooth, 2G, 3G, 4G, 5G, WIFI, sub1G, ZigBee or a custom wireless transmission protocol.

In the embodiments shown in FIGS. 2-5, the wireless modules of the wireless current sensor and the electrical parameter measurement and calculation apparatus may be the same or different, the wireless synchronization units of the wireless current sensor and the electrical parameter measurement and calculation apparatus may be the same or different, and the wireless transmission units of the wireless current sensor and the electrical parameter measurement and calculation apparatus may be the same or different.

Based on the structure of the above electrical parameter measurement and calculation apparatus, the application also provides an electrical parameter measurement and calculation method, which comprises the following steps.

In step 1, a current signal is received in a wireless manner.

A wireless transmission unit of a wireless module of an electrical parameter measurement and calculation apparatus receives a current signal from a wireless current sensor in a wireless manner, and transmits the current signal to an electrical parameter calculation module of the electrical parameter measurement and calculation apparatus, wherein the wireless transmission can be realized through Bluetooth, 2G, 3G, 4G, 5G, WIFI, sub1G, ZigBee or a custom wireless transmission protocol.

In step 2, a voltage signal is acquired.

A voltage acquisition module of the electrical parameter measurement and calculation apparatus acquires a voltage signal and transmits the voltage signal to the electrical parameter calculation module of the electrical parameter measurement and calculation apparatus. In one embodiment, when the voltages of multiple lines need to be acquired, the voltage acquisition module comprises multiple measurement points, and the voltages of multiple lines can be acquired through the multiple measurement points by sharing a common voltage reference point.

In step 3, electrical parameter information is calculated according to the current signal and the voltage signal.

The electrical parameter calculation module of the electrical parameter measurement and calculation apparatus calculates the electrical parameter information according to the received current signal and voltage signal.

Before the electrical parameter measurement and calculation apparatus and the wireless current sensor acquire and transmit signals, they need to keep the signal sampling time synchronized. In this way, the electrical parameter measurement and calculation method also comprises: performing sampling time synchronization of the voltage signal and the current signal by means of GNSS timing or 5G timing, or transmitting local clock information through a custom wireless transmission protocol or receiving local clock information of an opposite end through a custom wireless transmission protocol to perform sampling time synchronization of the voltage signal and the current signal.

The sampling time synchronization of the voltage signal and the current signal is realized through a wireless module or wireless synchronization unit. In one embodiment, the wireless modules or wireless synchronization units of the wireless current sensor and the electrical parameter measurement and calculation apparatus can accurately realize the sampling time synchronization of the voltage signal and the current signal after obtaining standard time information by using timing devices, such as GNSS and 5G modules. In another embodiment, the wireless module or wireless synchronization unit of the wireless current sensor or the electrical parameter measurement and calculation apparatus adopts a wireless radio frequency module (for example, by means of Bluetooth, 2G, 3G, 4G, 5G, WIFI, sub1G, ZigBee or a custom wireless transmission protocol) to send time information of a local clock to the opposite wireless module or wireless synchronization unit, and then accurately realize the signal sampling time synchronization through corresponding algorithms, or receive the local clock information from the opposite wireless module or wireless synchronization unit to realize the signal sampling time synchronization. The wireless module or wireless synchronization unit features small jitters (such as within 10 μs) and small time delays. The local clock information can be in the form of a series of pulses and/or timestamps. These pulses can directly control the sampling of the analog-to-digital conversion module or control the sampling of the analog-to-digital conversion module after computational processing. For example, when the pulse frequency of wireless transmission and reception is lower than the pulse frequency of actual sampling, the computational processing comprises frequency doubling. The time stamp can express more information about the local clock. For example, the time stamp may contain specific time information, such as date, hour, minute and second, or some agreed numerical serial number, which represents relative time, so as to achieve correct clock synchronization with the opposite end. The time error between the clock information received and restored by the wireless module or wireless synchronization unit of the wireless current sensor and the local clock information sent by the wireless module or wireless synchronization unit of the electrical parameter measurement and calculation apparatus should not exceed 20 μs, or the time error between the clock information received and restored by the wireless module or wireless synchronization unit of the electrical parameter measurement and calculation apparatus and the local clock information sent by the wireless module or wireless synchronization unit of the wireless current sensor should not exceed 20 μs. In this way, the wireless current sensor and the analog-to-digital conversion module of the electrical parameter measurement and calculation apparatus synchronously sample the respective signals at equal intervals, to realize the synchronization of voltage and current signals, thus ensuring the accuracy of electrical parameter calculation, for example, the measurement accuracy of power and/or electric energy is over 2%.

In the embodiments shown in FIGS. 1-5, the electrical parameter measurement and calculation system comprises the wireless current sensor and the electrical parameter measurement and calculation apparatus, that is, the built-in voltage acquisition module of the electrical parameter measurement and calculation apparatus obtains the voltage signal locally, and receives the current signal from the wireless current sensor through wireless transmission. In another embodiment, an electrical parameter measurement and calculation system may comprise a wireless voltage sensor and an electrical parameter measurement and calculation apparatus, that is, a built-in current acquisition module of the electrical parameter measurement and calculation apparatus obtains a current signal locally and receives a voltage signal from the wireless voltage sensor through wireless transmission. The combination of “wireless voltage sensor and electrical parameter measurement and calculation apparatus” is mainly different from that of “wireless current sensor and electrical parameter measurement and calculation apparatus” in electrical signal acquisition, one acquires the current signal through the wireless current sensor, while the other acquires the voltage signal through the wireless voltage sensor, and data transmission and reception, device synchronization, the electrical parameter calculation process and analog-to-digital conversion are basically the same. For example, the wireless voltage sensor performs data (for example, voltage signal) sending and receiving with the wireless transmission unit of the electrical parameter measurement and calculation apparatus through a wireless module or wireless transmission unit; for another example, the wireless modules or wireless synchronization units of the wireless voltage sensor and the electrical parameter measurement and calculation apparatus can accurately realize the signal sampling time synchronization after obtaining standard time information by using timing devices, such as GNSS and 5G modules. Alternatively, the wireless module or wireless synchronization unit of the wireless voltage sensor or the electrical parameter measurement and calculation apparatus adopts a wireless radio frequency module (for example, by means of Bluetooth, 2G, 3G, 4G, 5G, WIFI, sub1G, ZigBee or a custom wireless transmission protocol) to send time information of a local clock to the opposite wireless module or wireless synchronization unit, and then accurately realize the signal sampling time synchronization through corresponding algorithms, or receive the local clock information from the opposite wireless module or wireless synchronization unit to realize the signal sampling time synchronization. For another example, an analog-to-digital conversion module of the wireless voltage sensor and an analog-to-digital conversion module of the electrical parameter measurement and calculation apparatus convert an analog voltage signal or analog current signal into a digital voltage signal or digital current signal under synchronous signal sampling information.

Compared with the combination of “wireless current sensor and electrical parameter measurement and calculation apparatus”, the combination of “wireless voltage sensor and electrical parameter measurement and calculation apparatus” has a larger error in voltage measurement due to the voltage drop in the transmission process of the voltage signal, so the voltage signal should be acquired as close as possible to the measured object. The voltage signal is acquired by sharing a common voltage signal reference point. In this way, when three wireless voltage sensors are needed, the common voltage reference point will share three wire clips of the three wireless voltage sensors, which will cause wire clip congestion. However, since the same current flows through the same transmission line, the current signal can be acquired by the electrical parameter measurement and calculation apparatus at any position on the line. For the combination of “wireless current sensor and electrical parameter measurement and calculation apparatus”, the current signal can be acquired by establishing a current loop or current clamp around a transmission line, the electrical parameter measurement and calculation apparatus can acquire the voltage signal at a place close to the measured object, and the acquisition of three voltage signals is realized with only four wire clips.

Both combinations can be adopted when one electrical signal needs to be acquired. When multiple electrical signals need to be acquired, the combination of “wireless voltage sensor and electrical parameter measurement and calculation apparatus” will correspond to three wireless voltage sensors and six wire clips, and three of the wire clips share a common voltage reference point, resulting in wire clips congestion. In the combination of “wireless current sensor and electrical parameter measurement and calculation apparatus”, the number of wire clips for voltage acquisition is reduced to four, sharing of a common voltage reference point by multiple wire clips is avoided, and the wireless current sensor can select a suitable position to acquire the current signal according to the usage scene, so the combination of “wireless current sensor and electrical parameter measurement and calculation apparatus” is more advantageous. When electricity meter calibration is involved, it is necessary to acquire a pulse signal of a measured electricity meter at the same time and send the pulse signal to the electrical parameter measurement and calculation apparatus for operation, in which case the combination of “wireless current sensor and electrical parameter measurement and calculation apparatus” is also more advantageous.

In this application, the wireless current sensor and the wireless voltage sensor are collectively referred to as “wireless electrical sensors”, and accordingly, the voltage acquisition module or current acquisition module of the electrical parameter measurement and calculation apparatus and the current acquisition module or voltage acquisition module in the wireless current sensor or wireless voltage sensor are collectively referred to as “electrical signal acquisition module”.

In the embodiments shown in FIGS. 4 and 5, in order to obtain data from the electrical parameter measurement and calculation apparatus and control the operation of the electrical parameter measurement and calculation apparatus, the electrical parameter measurement and calculation apparatus can be provided with a human-computer interaction device. The human-computer interaction device comprises an input apparatus and an output apparatus. The input apparatus can receive input digital or character information as well as key signal input, such as sound input, voice input, touch screen input, and mouse input. The output apparatus may comprise a display device, a sound device, an auxiliary lighting device, and the like. The electrical parameter measurement and calculation apparatus can also communicate with a terminal device in a wired or wireless manner, and a user can input and output feedback through the terminal device, which facilitates user operation.

The technical scheme of the invention can be applied to high-precision devices with electrical parameter measurement and/or electricity meter calibration functions, low-precision devices such as phase voltammeters, and can also be applied to devices such as power quality analyzers, portable PMU synchronous phasor measurement apparatuses, power consumption testers, power analyzers, six-way differential protection vector testers, double clamp grounding resistance testers, storage recorders, portable multifunctional electricity meters, oscilloscopes, and digital multimeters.

A number of embodiments are given below to illustrate the application of the scheme of the invention to specific devices.

Embodiment 1: High-Precision Device with Electrical Parameter Measurement and/or Electricity Meter Calibration Functions

FIG. 6 is a structural diagram of a high-precision device with electrical parameter measurement and/or electricity meter calibration functions according to an embodiment of the invention. As shown in FIG. 6, the device with electrical parameter measurement and/or electricity meter calibration functions comprises an electrical parameter measurement and calculation apparatus and wireless current sensors (one or three wireless current sensors are provided based on whether a measured electricity meter is of a single phase or three phases). The electrical parameter measurement and calculation apparatus and the wireless current sensor synchronize the signal sampling time through their wireless modules or wireless synchronization units respectively. The electrical parameter measurement and calculation apparatus measures analog voltage signals (one or three voltage signals) accessed by the measured electricity meter, converts the analog voltage signals into digital voltage signals through an analog-to-digital conversion module, and then sends them to an electrical parameter calculation module. The wireless current sensor measures an analog current signal accessed by the measured electricity meter under the synchronous signal sampling information, converts the analog current signal into a digital current signal through the analog-to-digital conversion module, and then transmits the digital current signal to a wireless module or wireless transmission unit of the electrical parameter measurement and calculation apparatus through a wireless module or wireless transmission unit. The wireless module or wireless transmission unit of the electrical parameter measurement and calculation apparatus transmits the received current information to the electrical parameter calculation module of the electrical parameter measurement and calculation apparatus. The electrical parameter calculation module calculates standard electrical parameter information (such as voltage, current, inter-voltage phase, inter-current phase, inter-voltage and current phase, frequency, phase sequence, active power, reactive power, apparent power, and power factor) according to the voltage signals tested by the electrical parameter measurement and calculation apparatus and the received current signal, at the same time, the electrical parameter measurement and calculation apparatus reads an electric pulse signal of the measured electricity meter and calculates actual electrical parameter information of the electricity meter according to the electric pulse signal, and the electrical parameter measurement and calculation apparatus calculates and processes the standard electrical parameter information and the actual electrical parameter information to obtain an electric energy metering error of the measured electricity meter.

In this embodiment, the wireless current sensor is used for acquiring the current signal, and the electrical parameter measurement and calculation apparatus is used for acquiring the voltage signal and then calculating electrical parameters, or the wireless voltage sensor is used for acquiring the voltage signal and the electrical parameter measurement and calculation apparatus is used for acquiring the current signal and then calculating electrical parameters. In this embodiment, a wireless pulse receiver can also be used for acquiring a pulse signal.

In an alternative embodiment, the device with electrical parameter measurement and/or electricity meter calibration functions can be provided with a human-computer interaction module, which comprises an input apparatus and an output apparatus. A user directly interacts with the device with electrical parameter measurement and/or electricity meter calibration functions through the input apparatus and the output apparatus.

In another alternative embodiment, the device with electrical parameter measurement and/or electricity meter calibration functions communicates with a terminal device in a wired or wireless manner, and a user can input and output feedback through the terminal device.

FIG. 7 is a structural diagram of another high-precision device with electrical parameter measurement and/or electricity meter calibration functions according to an embodiment of the invention. As shown in FIG. 7, the terminal device can communicate with a marketing system through a mobile network.

This calibration device can also calibrate indicating meters such as a voltmeter, an ammeter, a power meter and a phase meter, as well as various three-phase three-wire, three-phase four-wire or single-phase active and reactive electricity meters.

Embodiment 2: Low-Precision Device Such as Phase Voltammeter

FIG. 8 is a structural diagram of a phase voltammeter according to an embodiment of the invention. As shown in FIG. 8, the phase voltammeter comprises an electrical parameter measurement and calculation apparatus and wireless current sensors (one to three wireless current sensors are provided based on electrical parameters to be measured). The electrical parameter measurement and calculation apparatus and the wireless current sensor synchronize the signal sampling time through their wireless modules or wireless synchronization units respectively. The electrical parameter measurement and calculation apparatus measures analog voltage signals (one to three voltage signals), converts the analog voltage signals into digital voltage signals through an analog-to-digital conversion module, and then sends them to an electrical parameter calculation module. The wireless current sensor measures an analog current signal, converts the analog current signal into a digital current signal through the analog-to-digital conversion module, and then transmits the digital current signal to a wireless module or wireless transmission unit of the electrical parameter measurement and calculation apparatus through a wireless module or wireless transmission unit. The wireless module or wireless transmission unit of the electrical parameter measurement and calculation apparatus transmits the received current information to the electrical parameter calculation module of the electrical parameter measurement and calculation apparatus. An electrical parameter calculation unit completes the measurement of other electrical parameter information (such as inter-voltage phase, inter-current phase, inter-voltage and current phase, frequency, phase sequence, active power, reactive power, apparent power, power factor, and sum of current vectors) according to the voltage signals tested by the electrical parameter measurement and calculation apparatus and the received current signal.

In this embodiment, the wireless current sensor is used for acquiring the current signal, and the electrical parameter measurement and calculation apparatus is used for acquiring the voltage signal and then calculating electrical parameters, or the wireless voltage sensor is used for acquiring the voltage signal and the electrical parameter measurement and calculation apparatus is used for acquiring the current signal and then calculating electrical parameters.

In one embodiment, the phase voltammeter can be provided with a human-computer interaction module. The human-computer interaction module comprises an input apparatus and an output apparatus. A user directly interacts with the phase voltammeter through the input apparatus and the output apparatus.

With the above-mentioned measurement function, the instrument can be used in many fields, mainly including: discrimination of inductive and capacitive circuits; relay protection of the phase relationship between different groups of CT; transformer wiring group inspection; checking of the wiring correctness of electricity meters; checking of the running speed of electricity meters; secondary loop inspection; and being used as a leakage ammeter.

Embodiment 3: Power Quality Analyzer

A power quality analyzer is a device for measuring the power quality of a power system.

FIG. 9 is a structural diagram of a power quality analyzer according to an embodiment of the invention. As shown in FIG. 9, the power quality analyzer comprises an electrical parameter measurement and calculation apparatus and a wireless current sensor. The wireless current sensor acquires four current signals, namely the current signals of live wires L1, L2, and L3 and a neutral wire, and the electrical parameter measurement and calculation apparatus acquires four voltage signals, namely the voltage signals of the live wires L1, L2, and L3 and the neutral wire. The electrical parameter measurement and calculation apparatus and the wireless current sensor synchronize the signal sampling time through their wireless modules or wireless synchronization units respectively. The electrical parameter measurement and calculation apparatus measures an analog voltage signal accessed by a measured object, converts the analog voltage signal into a digital voltage signal through an analog-to-digital conversion module, and then sends it to an electrical parameter calculation module. The wireless current sensor measures an analog current signal accessed by the measured object under the synchronous signal sampling information, converts the analog current signal into a digital current signal through the analog-to-digital conversion module, and then transmits the digital current signal to a wireless module or wireless transmission unit of the electrical parameter measurement and calculation apparatus through a wireless module or wireless transmission unit. The wireless module or wireless transmission unit of the electrical parameter measurement and calculation apparatus transmits the received current information to the electrical parameter calculation module of the electrical parameter measurement and calculation apparatus. The electrical parameter calculation module calculates power quality information according to the voltage signal tested by the electrical parameter measurement and calculation apparatus and the received current signal.

The power quality analyzer can measure and monitor power quality online in real time. Power quality monitoring indicators include voltage fluctuation and flicker, frequency deviation, harmonics, interharmonics, voltage deviation, overvoltage, overcurrent, voltage sag and short-term interruption, three-phase voltage imbalance, current imbalance, sudden rise and fall, transient state and other power quality parameters. The power quality analyzer can be widely used in power generation, supply and distribution systems for real-time monitoring and measurement of power quality.