Capacitance coupling type power grid open-phase signal collector
By acquiring three-phase current, overall current, and zero-sequence sampling signals through a capacitively coupled power grid phase loss signal acquisition device, the problem of equipment damage caused by power grid phase loss is solved, and stable operation of the power grid and equipment protection are achieved.
Patent Information
- Application Number
- CN202423058771.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-11-25
- Estimated Expiration
- 2034-12-11
AI Technical Summary
In existing technologies, the problem of power grid phase loss causing damage to transformer and electrical equipment has not been effectively solved.
A capacitively coupled power grid phase loss signal acquisition device is adopted. Through coupling capacitors, signal acquisition device and phase loss transmitter, three-phase current signal, overall current signal and zero-sequence sampling signal are acquired to determine whether there is a phase loss in the power grid and generate a fault indication signal.
It enables timely detection and repair of phase loss problems in the power grid, avoids damage to power equipment and electrical appliances, and ensures stable operation of the power grid.
Smart Images
Figure CN223597778U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electronic components, and more specifically to a capacitively coupled power grid phase loss signal acquisition device. Background Technology
[0002] In the modern energy landscape, the power grid is the "lifeline" for transmitting electricity and maintaining operations, and its stable operation is crucial. However, the power grid is frequently tested by nature. Extreme weather events such as strong winds, lightning, and hail, as well as oxidation and weathering, pose numerous safety hazards. In strong winds, overhead transmission lines are pulled and swayed by the strong winds, and the joints cannot withstand the impact. Screws shift, nuts loosen, and in severe cases, joints crack or even break, causing a phase loss in the power grid. During lightning strikes, direct lightning brings extremely high voltage and current, impacting line joints, causing them to heat up, deform, and melt solder joints. Induced lightning can also subject joints to additional voltage stress, causing structural damage, loosening, and cracking, leading to a phase loss. When hail strikes, dense hailballs hit the power grid, damaging the metal surface, increasing resistance, and making joints fragile and prone to breakage, causing a phase loss in the power grid. Everyday oxidation and weathering should not be underestimated. Joints rust when in contact with oxygen and moisture, and wind and sand accelerate wear, resulting in increased contact resistance, poor contact, and the potential for a phase loss.
[0003] The dangers of power grid phase loss are immense. Transformers can suffer from magnetic circuit imbalance, core overheating, and insulation aging. Switchgear components can be damaged, contacts can become abnormal, leading to easy failure and even shutdown. For consumer equipment, a single phase loss can cause large motors in factories to overheat and burn out, central air conditioning systems in office buildings to malfunction or even catch fire, and household appliances to malfunction or burn out, resulting in losses to daily life and the economy. Therefore, preventing power grid phase loss has become a crucial task for the power industry to ensure power supply and socio-economic stability. Utility Model Content
[0004] This utility model provides a capacitively coupled power grid phase loss signal acquisition device to solve the problem of damage to power equipment and electrical appliances caused by power grid phase loss.
[0005] This utility model embodiment provides a capacitively coupled power grid phase loss signal acquisition device, including:
[0006] The coupling capacitor has its input terminals electrically connected to the three-phase circuit of the power grid, and its three output terminals electrically connected to the signal acquisition unit.
[0007] The signal acquisition unit is electrically connected to the three output terminals of the coupling capacitor, and is used to acquire the three-phase current signal, the overall current signal and the zero-sequence sampling signal, respectively.
[0008] The phase loss transmitter, which is electrically connected to the signal sampler, is used to generate a fault indication signal or a normal indication signal based on the three-phase current signal, the overall current signal and the zero-sequence sampling signal.
[0009] Preferably, the coupling capacitor comprises three high-voltage ceramic pillars;
[0010] Each of the high-voltage ceramic cylinders includes a first capacitor and a second capacitor connected in parallel.
[0011] The first input terminal, formed by the parallel connection of the first capacitor and the second capacitor, is electrically connected to any one phase of the three-phase circuit.
[0012] The three first capacitors are connected in parallel and then connected in series with the third capacitor to form a zero-sequence sampling terminal;
[0013] The three second capacitors each pass through a Rogowski coil, and the three Rogowski coils form a three-phase current sampling terminal;
[0014] The three second capacitors are integrated through a Rogowski coil, which forms an integral current sampling terminal.
[0015] Preferably, the signal sampling terminal includes three sampling terminals;
[0016] The first acquisition terminal, which is electrically connected to the zero-sequence sampling terminal, is used to acquire the zero-sequence sampling signal;
[0017] The second acquisition terminal, which is electrically connected to the three Rogowski coils to form a three-phase current sampling terminal, is used to acquire the three-phase current signal.
[0018] The third acquisition terminal, which is electrically connected to the Rogowski coil to form an overall current sampling terminal, is used to acquire the overall current signal.
[0019] Preferably, the phase loss transmitter includes a signal input module, a conversion module, a logic judgment circuit, and an output module;
[0020] The signal input module is used to receive three-phase current signals, overall current signals and zero-sequence sampling signals from the signal acquisition terminal;
[0021] The conversion module is used to convert three-phase current signals, overall current signals, and zero-sequence sampled signals into digital signals.
[0022] The logic judgment circuit is used to send a normal or abnormal signal to the output module based on the specific values of the zero-sequence sampling signal, the overall current signal, and the three-phase current signal.
[0023] The output module is electrically connected to the logic judgment circuit and is used to send the normal or abnormal signal to the control center.
[0024] This utility model provides a capacitively coupled power grid phase loss signal acquisition device, comprising: a coupling capacitor, whose input terminals are electrically connected to the three-phase circuit of the power grid, and whose three output terminals are electrically connected to a signal acquisition device; a signal acquisition device, which is electrically connected to the three output terminals of the coupling capacitor, and is used to acquire three-phase current signals, overall current signals, and zero-sequence sampling signals; and a phase loss transmitter, which is electrically connected to the signal acquisition device, and is used to generate fault indication signals or normal indication signals based on the three-phase current signals, overall current signals, and zero-sequence sampling signals. Based on the coupling capacitor and the signal acquisition device, this device can acquire the zero-sequence sampling signals, overall current signals, and three-phase current signals of the three-phase circuit. Furthermore, by analyzing the current changes in the zero-sequence sampling signals, overall current signals, and three-phase current signals, a phase loss problem existing in the power grid operation can be determined. Based on this, the phase loss power grid can be repaired, avoiding damage to transformer equipment and electrical equipment caused by phase loss in the power grid. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a schematic diagram of a capacitively coupled power grid phase loss signal acquisition device provided in the prior art.
[0027] Figure 2 A schematic diagram of the coupling capacitor structure provided for an example of this utility model;
[0028] Among them, 1 is the coupling capacitor, 2 is the signal acquisition unit, 3 is the phase loss transmitter, 11 is the high voltage ceramic column, 12 is the zero-sequence sampling terminal, 13 is the three-phase current sampling terminal, 14 is the overall current sampling terminal, 15 is the Rogowski coil, 16 is the first capacitor, 17 is the second capacitor, and 18 is the third capacitor. Detailed Implementation
[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0030] Figure 1 This is a schematic diagram of a capacitively coupled power grid phase loss signal acquisition device provided in the prior art. Figure 2 A schematic diagram of the coupling capacitor structure provided for an embodiment of this utility model. The following uses... Figure 1 and Figure 2 Taking this example, we will introduce in detail the capacitively coupled power grid phase loss signal acquisition device provided in the embodiments of this utility model.
[0031] Specifically, such as Figure 1 As shown, the capacitor-coupled power grid phase loss signal acquisition device includes a coupling capacitor 1, a signal acquisition device 2, and a phase loss transmitter 3.
[0032] The input terminals of the coupling capacitors are electrically connected to the three-phase circuit of the power grid, and the three output terminals of the coupling capacitors are electrically connected to the signal acquisition unit. The signal acquisition unit is electrically connected to the three output terminals of the coupling capacitors and is used to acquire the three-phase current signal, the overall current signal, and the zero-sequence sampling signal, respectively. The phase loss transmitter is electrically connected to the signal sampler and is used to generate a fault indication signal or a normal indication signal based on the three-phase current signal, the overall current signal, and the zero-sequence sampling signal.
[0033] In this capacitively coupled power grid phase loss signal acquisition device, the coupling capacitor is used to couple the three-phase AC power signal of the power grid to the signal acquisition device. The signal acquisition device is used to collect these signals and transmit the collected three-phase current signal, overall current signal and zero-sequence sampling signal to the phase loss transmitter. The phase loss transmitter is used to analyze these signals and determine whether there is a phase loss in the power grid based on these signal conditions.
[0034] For example, the capacitively coupled power grid phase loss signal acquisition device provided in this embodiment of the present invention includes coupling capacitors that can be as follows: Figure 2 As shown, it includes three high-voltage ceramic pillars 11, and the input terminals of the three high-voltage ceramic pillars are respectively located on the upper side of the high-voltage ceramic pillars, for electrical connection with the three-phase circuit respectively.
[0035] Specifically, each high-voltage ceramic column includes a first capacitor 16 and a second capacitor 17 connected in parallel; wherein, the first input terminal formed by the parallel connection of the first capacitor and the second capacitor is electrically connected to any one phase of the three-phase current circuit; the three first capacitors are connected in parallel and then connected in series with the third capacitor 18, one end of which forms the zero-sequence sampling terminal 12, and the other end is grounded; the three second capacitors respectively pass through a Rogowski coil 15, and the three Rogowski coils form the three-phase current sampling terminal 13; the three second capacitors are integrated and simultaneously pass through a Rogowski coil, and this Rogowski coil forms the overall current sampling terminal 14.
[0036] In practical applications, three Rogowski coils are located at the low-voltage terminals of the second capacitors of the three phases A, B, and C, respectively. These Rogowski coils are used to measure current and are connected to external devices via BNC. Here, "BNC" is referred to as the three-phase current sampling terminal. The low-voltage terminals of the three second capacitors pass through a single Rogowski coil, which is used to measure current and is connected to external devices via an interface. Here, "interface" is referred to as the overall current sampling terminal. The third capacitor has one end connected to Ucom and the other end connected to the low-voltage terminal of the first capacitor. Here, "Ucom" is referred to as the zero-sequence sampling terminal.
[0037] It should be noted that the first capacitor is 250pF, the second capacitor is 4200pF, and the third capacitor is 900nF.
[0038] For example, the capacitively coupled power grid phase loss signal acquisition device provided in this embodiment of the present invention includes a first acquisition terminal, a second sampling terminal and a third sampling terminal.
[0039] The circuit includes a first acquisition terminal electrically connected to the zero-sequence sampling terminal for acquiring zero-sequence sampling signals. In this circuit, the zero-sequence current is generated at the low-voltage end of the first high-voltage capacitor (250pF). The second acquisition terminal electrically connected to the three Rogowski coils to form a three-phase current sampling terminal is used to acquire three-phase current signals. Here, the Rogowski coils are respectively wound around the low-voltage ends of the second high-voltage capacitors (4200pF) of phases A, B, and C to measure the current of each phase. The third acquisition terminal electrically connected to the Rogowski coils to form an overall current sampling terminal is used to acquire the overall current signal. Here, the low-voltage ends of the second high-voltage capacitors (4200pF) of phases A, B, and C are simultaneously connected to the Rogowski coils, which are used to measure the overall current signal.
[0040] For example, the capacitively coupled power grid phase loss signal acquisition device provided in this embodiment of the present invention has the main function of phase loss transmitter to determine whether there is a phase loss in the power grid by analyzing the input zero-sequence sampling signal, three-phase current signal and overall current signal.
[0041] Specifically, regarding the zero-sequence sampling signal, under normal three-phase balanced operation, the zero-sequence current is zero because the vector sum of the three-phase currents is zero; when a phase loss occurs, the zero-sequence current sum is not zero. Regarding the three-phase current signal, under normal conditions, the magnitudes of the three-phase current signals are approximately equal (under a balanced three-phase load), and their phases differ by 120°; when a phase loss occurs, the amplitude of the lost-phase current signal drops to zero. Simultaneously, the current signals of the other two phases will change due to load imbalance, and their amplitudes may increase, with the phase difference no longer exceeding 120°. Regarding the overall current signal, under normal conditions, the overall current signal is zero when the three phases are balanced; when a phase loss occurs, the overall current signal is no longer zero.
[0042] In practical applications, a phase loss transmitter includes a signal input module, a conversion module, a logic judgment circuit, and an output module. The signal input module receives three-phase current signals, the overall current signal, and the zero-sequence sampled signal from a signal acquisition terminal. The conversion module converts the three-phase current signals, the overall current signal, and the zero-sequence sampled signal into digital signals. The logic judgment circuit sends a normal or abnormal signal to the output module based on the specific values of the zero-sequence sampled signal, the overall current signal, and the three-phase current signal. The output module, electrically connected to the logic judgment circuit, sends the normal or abnormal signal to the control center.
[0043] It should be noted that the phase loss transmitter here can be a Chint phase loss and phase sequence protection relay XJ3-G, a Schneider phase sequence relay RM22TG20, or a Xinshida phase sequence relay SW11. The specific model of the phase loss transmitter is not limited here.
[0044] In summary, this utility model provides a capacitively coupled power grid phase loss signal acquisition device, comprising: a coupling capacitor, whose input terminals are electrically connected to the three-phase circuit of the power grid, and whose three output terminals are electrically connected to a signal acquisition device; a signal acquisition device, which is electrically connected to the three output terminals of the coupling capacitor, and is used to acquire three-phase current signals, overall current signals, and zero-sequence sampling signals; and a phase loss transmitter, which is electrically connected to the signal acquisition device, and is used to generate fault indication signals or normal indication signals based on the three-phase current signals, overall current signals, and zero-sequence sampling signals. Based on the coupling capacitor and the signal acquisition device, this device can acquire the zero-sequence sampling signals, overall current signals, and three-phase current signals of the three-phase circuit. Furthermore, by analyzing the current changes in the zero-sequence sampling signals, overall current signals, and three-phase current signals, a phase loss problem existing in the power grid operation can be determined. Based on this, the phase loss power grid can be repaired, avoiding damage to transformer equipment and electrical equipment caused by phase loss in the power grid.
[0045] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.
[0046] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.
Claims
1. A capacitively coupled power grid phase loss signal acquisition device, characterized in that, include: The coupling capacitor has its input terminals electrically connected to the three-phase circuit of the power grid, and its three output terminals electrically connected to the signal acquisition unit. The signal acquisition unit is electrically connected to the three output terminals of the coupling capacitor, and is used to acquire the three-phase current signal, the overall current signal and the zero-sequence sampling signal, respectively. The phase loss transmitter, which is electrically connected to the signal sampler, is used to generate a fault indication signal or a normal indication signal based on the three-phase current signal, the overall current signal and the zero-sequence sampling signal.
2. The capacitively coupled power grid phase loss signal acquisition device as described in claim 1, characterized in that, The coupling capacitor comprises three high-voltage ceramic pillars; Each of the high-voltage ceramic cylinders includes a first capacitor and a second capacitor connected in parallel. The first input terminal, formed by the parallel connection of the first capacitor and the second capacitor, is electrically connected to any one phase of the three-phase circuit. The three first capacitors are connected in parallel and then connected in series with the third capacitor to form a zero-sequence sampling terminal; The three second capacitors each pass through a Rogowski coil, and the three Rogowski coils form a three-phase current sampling terminal; The three second capacitors are integrated through a Rogowski coil, which forms an integral current sampling terminal.
3. The capacitively coupled power grid phase loss signal acquisition device as described in claim 1, characterized in that, The signal sampling terminal includes three sampling terminals; The first acquisition terminal, which is electrically connected to the zero-sequence sampling terminal, is used to acquire the zero-sequence sampling signal; The second acquisition terminal, which is electrically connected to the three Rogowski coils to form a three-phase current sampling terminal, is used to acquire the three-phase current signal. The third acquisition terminal, which is electrically connected to the Rogowski coil to form an overall current sampling terminal, is used to acquire the overall current signal.
4. The capacitively coupled power grid phase loss signal acquisition device as described in claim 1, characterized in that, The phase loss transmitter includes a signal input module, a conversion module, a logic judgment circuit, and an output module; The signal input module is used to receive three-phase current signals, overall current signals and zero-sequence sampling signals from the signal acquisition terminal; The conversion module is used to convert three-phase current signals, overall current signals, and zero-sequence sampled signals into digital signals. The logic judgment circuit is used to send a normal or abnormal signal to the output module based on the specific values of the zero-sequence sampling signal, the overall current signal, and the three-phase current signal. The output module is electrically connected to the logic judgment circuit and is used to send the normal or abnormal signal to the control center.