Secondary voltage receiving device of high-voltage divider

Abstract

The invention discloses a secondary voltage receiving device of a high-voltage divider, which is arranged at an output port of a low-voltage arm of the voltage divider and comprises a voltage follower module, an attenuator module, an acquisition card module and a signal receiving end module, and the voltage follower module is used for isolating and amplifying a received voltage signal output by the low-voltage arm of the voltage divider; the amplified voltage is output and transmitted to the attenuator module; the attenuator module attenuates the amplified voltage and outputs an attenuated signal; and the acquisition card module is fixed at a preset position away from the follower module and is used for converting the received attenuation signal into a digital signal and transmitting the digital signal to the signal receiving end module.

Description

Technical Field

[0001] The present application relates to the field of ultra-high voltage technology, and in particular to a secondary voltage receiving device for a high voltage voltage divider. Background Art

[0002] In recent years, my country's new energy has developed rapidly. Photovoltaic, wind power and other new energy sources are different from traditional fossil energy power generation. Their main characteristics are that they are significantly affected by environmental and climate characteristics and have obvious randomness, volatility and intermittent characteristics. In addition, distributed new energy sources use a large number of power electronic equipment such as inverters to generate high-frequency oscillation waveforms in the power grid with frequencies close to integer multiples of the switching frequency. In the "double high" power system, the voltage and current states of the power grid will show wide dynamic characteristics in the time domain and frequency domain. Traditional voltage sensors can accurately measure the power frequency and harmonic voltages within a certain range (<2kHz), but cannot accurately measure wide dynamic voltage signals, which in turn affects the accuracy of the action of the power metering and control protection system, and seriously affects the safe and stable operation of the power system. In addition, there is a lack of effective technical means for the wide dynamic performance evaluation method of high-voltage voltage transformers.

[0003] The level of power frequency voltage measurement in my country has reached the international advanced level. For power frequency voltage, electromagnetic voltage transformers and capacitive voltage transformers can accurately and reliably measure voltage signals. When the measured voltage is power frequency voltage and high-order and ultra-high-order harmonic aliasing signals, the measurement error of electromagnetic voltage transformers and capacitive voltage transformers increases significantly due to their narrow bandwidth; the transient overvoltage measurement device mainly achieves waveform reproduction by constructing a distributed capacitor voltage divider or an electric field measurement device, and the measurement accuracy is low, and the measurement error is generally greater than 3%. Therefore, there are few related studies on voltage sensing devices that can accurately reproduce broadband voltages from power frequency to hundreds of kHz and ensure the measurement accuracy of power frequency and harmonics. The measurement methods that can measure power frequency and broadband voltage include measurement methods based on resistance, capacitance and resistor-capacitor voltage division: the parallel resistor-capacitor voltage division structure is currently the most effective and reliable structure for broadband voltage measurement. The biggest problem with this type of voltage divider is that long-term parallel operation will bring potential risks to system safety. Summary of the invention

[0004] In view of the problems existing in the above background technology, the present disclosure provides a secondary voltage receiving device of a high-voltage voltage divider.

[0005] According to one aspect of the present application, a high-voltage voltage divider secondary voltage receiving device is provided, which is arranged at the output port of the low-voltage arm of the voltage divider, and includes: a voltage follower module, an attenuator module, an acquisition card module and a signal receiving end module, wherein

[0006] The voltage follower module is used to isolate and amplify the voltage signal output by the low-voltage arm of the voltage divider, output the amplified voltage and transmit it to the attenuator module;

[0007] The attenuator module attenuates the amplified voltage and outputs an attenuated signal;

[0008] The acquisition card module is fixed at a predetermined position of the distance follower module, and is used to convert the received attenuated signal into a digital signal and transmit it to the signal receiving end module.

[0009] Optionally, the voltage follower module includes: a bias reference module, an operational amplifier and feedback module, and an impedance isolation module, wherein

[0010] The voltage signal output by the low-voltage arm of the voltage divider flows through the bias reference module, the operational amplifier and feedback module, and the impedance isolation module in sequence. The bias reference module suppresses zero drift by adjusting the value of the adjustable resistor and capacitor. The operational amplifier and feedback module are used to reduce external signal interference. The impedance isolation module is used to isolate the power supply and small signals.

[0011] Optionally, the attenuator module includes: an attenuator and an attenuation ratio adjustment module arranged in the attenuator, wherein:

[0012] The attenuator is a hybrid structure of adjustable resistors and capacitors;

[0013] The attenuation ratio adjustment module adjusts the hybrid structure of the adjustable resistor and capacitor through the required attenuation ratio, resistance value and capacitance value.

[0014] Optionally, the attenuation ratio can be adjusted with an accuracy of 1%.

[0015] Optionally, the acquisition card module includes: an acquisition card and a wireless transmission module, wherein the acquisition card is used to convert the attenuated signal into a digital signal, and the wireless transmission module is used to transmit the digital signal to the signal receiving end module.

[0016] Optionally, the acquisition card module transmits the digital signal to the signal receiving end module via a wireless network.

[0017] Therefore, the present application uses a voltage follower module to isolate and amplify the voltage signal output by the low-voltage arm of the voltage divider, output the amplified voltage and transmit it to the attenuator module; the attenuator module attenuates the amplified voltage and outputs an attenuated signal; the acquisition card module is fixed at a predetermined position from the follower module, and is used to convert the received attenuated signal into a digital signal and transmit it to the signal receiving end module. According to the above technology and device of the secondary voltage receiving module of the high-voltage voltage divider based on impedance isolation technology, the output signal can be kept unaffected by the secondary load capacitance while ensuring that the output signal amplitude and frequency remain unchanged, thereby ensuring accurate monitoring of high-frequency signals of the ultra-high voltage power grid.

[0018] Based on the detailed description of the specific embodiments of the present application in combination with the accompanying drawings below, those skilled in the art will become more aware of the above and other objects, advantages and features of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Hereinafter, some specific embodiments of the present application will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0020] Figure 1 is a schematic diagram of a secondary signal receiving device of a UHV voltage divider according to an embodiment of the present application;

[0021] Figure 2 yes Figure 1 The voltage follower system block diagram is shown;

[0022] Figure 3 It is a schematic diagram of a secondary voltage receiving module device of a high-voltage voltage divider based on impedance isolation technology according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] In order to enable those skilled in the art to better understand the scheme of the present disclosure, the technical scheme in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present disclosure.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so as to describe the embodiments of the present disclosure described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0027] Figure 1 is a structural diagram of a secondary voltage receiving device of a high voltage divider according to an embodiment of the present application, with reference to Figure 1 As shown, the secondary voltage receiving device of the high voltage divider is arranged at the output port of the low voltage arm of the voltage divider, and includes: a voltage follower module, an attenuator module, an acquisition card module and a signal receiving end module, wherein

[0028] The voltage follower module is used to isolate and amplify the voltage signal output by the low-voltage arm of the voltage divider, output the amplified voltage and transmit it to the attenuator module;

[0029] The attenuator module attenuates the amplified voltage and outputs an attenuated signal;

[0030] The acquisition card module is fixed at a predetermined position of the distance follower module, and is used to convert the received attenuated signal into a digital signal and transmit it to the signal receiving end module.

[0031] Specifically, the purpose of the present invention is to provide a technology and device for a high-voltage voltage divider secondary voltage receiving module based on impedance isolation technology, which makes the output signal unaffected by the secondary load capacitance and ensures accurate monitoring of high-frequency signals of ultra-high voltage power grid.

[0032] In order to achieve the above purpose, refer to Figure 1 As shown, ① capacitor voltage divider; ② follower; ③ attenuator; ④ acquisition card and computer terminal. The present invention provides a high-voltage voltage divider secondary voltage receiving device, including: a voltage follower module ( Figure 2 and Figure 3 ①②③)、attenuator module( Figure 3 ④⑤), acquisition card module ( Figure 3 ⑥) and the signal receiving terminal ( Figure 3 In ⑦), the secondary voltage signal of the high voltage divider is received. Its characteristics are as follows:

[0033] First, the voltage signal output by the low-voltage arm of the voltage divider is isolated and amplified by the voltage follower. The operational amplifier in the follower has a high input impedance, which can reach several MΩ at both low and high frequencies. The high input impedance can effectively reduce signal interference and improve the signal-to-noise ratio.

[0034] Secondly, the voltage follower has a smaller output impedance, better output current and load driving capability, which can ensure the voltage amplitude following function while improving the frequency response characteristics of the follower. At the same time, the follower has a good isolation capability, which can effectively isolate the front-stage and rear-stage circuits, which only improves the stability of the circuit and reduces the mutual influence between them.

[0035] Secondly, the output signal of the op amp passes through the high-voltage transistor, which has high-speed switching characteristics and strong load capacity, and can transmit the secondary voltage waveform without loss under the premise of achieving impedance isolation;

[0036] refer to Figure 2 As shown in the figure, ① bias reference unit; ② signal amplification unit; ③ isolation unit; ④ power supply. The voltage signal output by the voltage divider flows through the bias reference module, operational amplifier and feedback module and impedance isolation module in sequence. The bias reference module suppresses zero drift by adjusting the value of the adjustable resistance and capacitance. The operational amplifier and feedback module have high input impedance, which effectively reduces external signal interference. The impedance isolation module isolates the power supply and small signals, while improving the load capacity of the follower to achieve lossless transmission of the voltage signal.

[0037] Further, refer to Figure 3 As shown, ① bias reference module; ② operational amplifier and feedback module; ③ impedance isolation module; ④ attenuator; ⑤ attenuation ratio adjustment module; ⑥ acquisition card and wireless transmission module; ⑦ signal receiving terminal. Among them, the adjustable capacitor C1, the adjustable resistor R1 and the precision resistor R2 form a π-type circuit, which is connected to the positive input terminal of the operational amplifier. The output of the operational amplifier is connected to the base of the transistor Q1, the emitter of Q1 is connected to the resistor R3, and then connected to the negative input terminal of the operational amplifier. The collector of Q1 is connected to the attenuator, and the resistor R4 and the capacitor C4 are connected in series and then in parallel with R41. The resistor R5 is connected to the adjustable capacitor C5 and then in parallel with the adjustable resistor R51. Finally, the output signal is transmitted to the acquisition card.

[0038] The output voltage of the voltage follower is attenuated by the attenuator, which is a mixed structure of resistors and capacitors, among which C4 and C5 determine the attenuation ratio of the attenuator. Determines the dynamic response of the attenuator;

[0039] Furthermore, the attenuator has adjustable resistance and capacitance, and an attenuation ratio adjustment module is set. The adjustable resistance and capacitance are connected to the knob outside the device. Each position of the knob can adjust the attenuation ratio by 1%. First, the resistance and capacitance values ​​are calculated according to the required attenuation ratio and formula (2), and then the resistance and capacitance are adjusted synchronously according to the adjustment module. In the application, the coordinated adjustment is adjusted according to the falling edge square wave response. Thus, the attenuation ratio of the attenuator is not affected by stray capacitance. In different application scenarios, the resistance and capacitance values ​​can be fine-tuned to meet different measurement requirements;

[0040] Secondly, the acquisition card and attenuator are no longer connected by long-distance cables, but the acquisition card is directly fixed near the follower. The output signal of the attenuator is directly transmitted to the acquisition card and converted into a digital signal, which prevents the signal from being interfered during the transmission process and ensures the speed and accuracy of data acquisition.

[0041] Finally, WiFi wireless transmission technology is used to transmit the digital signal generated by the acquisition card to the computer terminal in the control area in real time and quickly, and the researchers analyze the signal.

[0042] (1) The input impedance of the voltage follower can reach the MΩ level, and the signal anti-interference ability is strong. At the same time, the output impedance of the follower is low and the load capacity is strong.

[0043] (2) A negative feedback loop is used to connect the output end of the amplifier to the feedback end. The function of the negative feedback circuit is to compare the output signal of the amplifier with the input signal and feed back the difference to the input end of the amplifier to maintain the stability of the output voltage.

[0044] (3) A high-voltage transistor is connected to the output end of the operational amplifier, and the high-speed switching characteristics and strong load-carrying capacity of the transistor are utilized to design an enhanced push-pull common emitter follower, which can transmit the secondary voltage waveform without loss while achieving impedance isolation.

[0045] (4) Fixed RC and adjustable RC are mixed to form an attenuator, such as Figure 2 As shown, the attenuation ratio can be adjusted according to actual conditions, and its transfer function can be expressed as:

[0046]

[0047] (5) The attenuation ratio of the designed attenuator is almost unaffected by stray capacitance, and the resistance and capacitance values ​​can be adjusted in coordination according to the attenuation ratio formula:

[0048]

[0049] In one embodiment of the present invention, the method for using the high voltage divider secondary voltage receiving module proposed in the present application is as follows:

[0050] Step 1: Integrate the voltage follower, attenuator and acquisition card together to reduce the stray capacitance interference and other interference sources of the secondary output voltage of the voltage divider, while reducing the volume of the impedance isolation module for easy installation and disassembly;

[0051] Step 2: Connect the device to the low-voltage arm output port of the voltage divider. The output signal of the voltage divider flows through the voltage follower and attenuator respectively, and is transmitted to the acquisition card to convert the analog signal into a digital signal.

[0052] The third step is that the acquisition card is equipped with a WiFi module, which can transmit the signal to the remote console computer terminal in real time through wireless communication technology;

[0053] Step 4: Researchers can directly analyze and process the data transmitted to the terminal in the control area.

[0054] In summary, the advantages and positive effects of the present invention are:

[0055] The present invention ensures that the output signal is not affected by the secondary load capacitance and other interference sources while ensuring that the output signal amplitude and frequency remain unchanged, thereby ensuring accurate monitoring of high-frequency signals in the high-voltage power grid. The present invention also reduces the volume of the secondary side load of the voltage divider, facilitates installation and maintenance, and improves engineering construction efficiency. It solves the difficulty of accurately measuring the wide dynamic high voltage and large current in the time-frequency domain of the "double-high" power system. The technology and device of the high-voltage voltage divider secondary voltage receiving module based on impedance isolation technology provided by the present invention can efficiently and accurately carry out wide-frequency ultra-high voltage measurements.

[0056] Thus, the present invention discloses a secondary voltage receiving device of a high-voltage voltage divider based on impedance isolation technology. First, the voltage signal output by the low-voltage arm of the voltage divider is first isolated and amplified by a voltage follower. The operational amplifier in the follower has a high input impedance, and its input impedance can reach several MΩ at both low and high frequencies. The high input impedance can effectively reduce signal interference and improve the signal-to-noise ratio; secondly, the voltage follower has a smaller output impedance, and the output current and load driving capabilities are better, so that the frequency response characteristics of the follower can be improved while ensuring the voltage amplitude following function. At the same time, the follower has a good isolation capability, which can effectively isolate the front-stage and rear-stage circuits, which not only improves the stability of the circuit and reduces the mutual influence between them; secondly, the output signal of the operational amplifier passes through a high-voltage transistor, which has a high-speed switching characteristic and a strong load-carrying capacity, and can transmit the voltage signal losslessly under the premise of realizing impedance isolation; secondly, the output voltage of the voltage follower is attenuated by an attenuator, which is a mixed structure of resistors and capacitors, wherein C4 and C5 determine the attenuation ratio of the attenuator, Determine the dynamic response of the attenuator; secondly, the attenuator has adjustable resistance and capacitance, and an attenuation ratio adjustment module is set. The adjustable resistance and capacitance are connected to the knob outside the device. Each knob position can adjust the attenuation ratio by 1%. First, calculate the resistance and capacitance values ​​according to the required attenuation ratio and formula (2), and then adjust the resistance and capacitance synchronously according to the adjustment module. In the application, adjust the coordinated adjustment according to the falling edge square wave response. Thus, the attenuation ratio of the attenuator is not affected by stray capacitance. In different application scenarios, the resistance and capacitance values ​​can be fine-tuned to meet different measurement needs. Secondly, the acquisition card and the attenuator are no longer connected by long-distance cables, but the acquisition card is directly fixed near the follower. The output signal of the attenuator is directly transmitted to the acquisition card and converted into a digital signal to prevent the signal from being interfered during the transmission process while ensuring the speed and accuracy of data acquisition. Finally, the digital signal generated by the acquisition card is transmitted to the computer terminal in the control area in real time and quickly using WiFi wireless transmission technology, and the researchers analyze the signal.

[0057] According to the above technology and device of the high-voltage voltage divider secondary voltage receiving module based on impedance isolation technology, the output signal can be kept unaffected by the secondary load capacitance while ensuring that the output signal amplitude and frequency remain unchanged, thereby ensuring accurate monitoring of high-frequency signals in the UHV power grid.

[0058] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present disclosure. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0059] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0060] In the description of the present disclosure, it is necessary to understand that the orientation or positional relationship indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present disclosure and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present disclosure; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0061] The above is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A secondary voltage receiving device for a high voltage divider, arranged at the output port of a low voltage arm of the voltage divider, characterized in that: include: A voltage follower module, an attenuator module, an acquisition card module and a signal receiving end module, wherein The voltage follower module is used to isolate and amplify the voltage signal output by the low-voltage arm of the voltage divider, output the amplified voltage and transmit it to the attenuator module; The attenuator module attenuates the amplified voltage and outputs an attenuated signal; The acquisition card module is fixed at a predetermined position away from the follower module, and is used to convert the received attenuated signal into a digital signal and transmit it to the signal receiving end module.

2. The method according to claim 1, characterized in that The voltage follower module includes: a bias reference module, an operational amplifier and a feedback module, and an impedance isolation module, wherein The voltage signal output by the low-voltage arm of the voltage divider flows through the bias reference module, the operational amplifier and feedback module, and the impedance isolation module in sequence. The bias reference module suppresses zero drift by adjusting the value of the adjustable resistor and capacitor. The operational amplifier and feedback module are used to reduce external signal interference. The impedance isolation module is used to isolate the power supply and small signals.

3. The method according to claim 1, characterized in that: The attenuator module comprises: an attenuator and an attenuation ratio adjustment module arranged in the attenuator, wherein: The attenuator is a hybrid structure of adjustable resistors and capacitors; The attenuation ratio adjustment module adjusts the hybrid structure of the adjustable resistor and capacitor according to the required attenuation ratio, resistance value and capacitance value.

4. The method according to claim 1, characterized in that: The adjustment accuracy of the attenuation ratio is 1%.

5. The method according to claim 1, characterized in that The acquisition card module includes: an acquisition card and a wireless transmission module, wherein the acquisition card is used to convert the attenuated signal into a digital signal, and the wireless transmission module is used to transmit the digital signal to the signal receiving end module.

6. The method according to claim 1, characterized in that The acquisition card module transmits the digital signal to the signal receiving end module via a wireless network.

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