Device for measuring converter transformer valve side alternating current voltage

Abstract

The utility model discloses a device used for measuring converter transformer valve side AC voltage, comprising a main body unit composed of a resistance-capacitance voltage divider and used for dividing AC-DC superposed voltage; and the secondary voltage dividing unit is connected in parallel with a capacitive voltage divider on an output terminal of the resistance-capacitance voltage divider and is used for isolating direct current voltage from the direct current component output by the main body unit. The problem of converter transformer valve side AC voltage measurement is solved.

Description

A device for measuring the AC voltage on the valve side of a converter transformer. Technical Field

[0001] This utility model relates to the field of high-voltage electrical equipment technology, specifically to a device for measuring the AC voltage on the side of a converter transformer valve. Background Technology

[0002] Compared with AC power transmission, DC power transmission has several advantages: (1) DC overhead lines only require positive and negative conductors, have simple tower structures, low line costs, and low losses. (2) DC cable lines have large transmission capacity, low cost, low losses, are not prone to aging, have long lifespans, and are not limited by transmission distance. (3) DC power transmission does not have the stability problems of AC power transmission, which is conducive to long-distance, large-capacity power transmission. (4) Using DC power transmission to achieve asynchronous interconnection between power systems does not increase the short-circuit capacity of the interconnected grid, and does not require the replacement of circuit breakers or the implementation of current limiting measures due to the increase in short-circuit capacity. (5) The active power transmitted by DC power transmission and the reactive power consumed by the converter can be controlled by the control system, and this rapid controllability can be used to improve the operating performance of AC systems. (6) Under the action of DC current, only the resistance plays a role, while the inductance and capacitance do not play a role. DC power transmission uses the earth as a loop, and the DC current flows deep into the earth with very low resistivity. (7) DC transmission can be easily constructed in phases and expanded, which is conducive to maximizing investment benefits. (8) The active power transmitted by DC transmission and the reactive power consumed by the converter stations at both ends can be quickly controlled manually and automatically, which is conducive to the economic operation and modern management of the power grid.

[0003] As early as 1882, Germany built a 2kV DC power transmission project. After more than a century of development, the highest voltage level of DC projects has now reached ±1100kV.

[0004] DC measuring devices are crucial equipment in DC engineering, primarily used to provide voltage signals for voltage metering, voltage monitoring, and relay protection devices. As shown in Figure 5, the location of DC measuring devices in modern DC systems includes the converter side and pole lines, mainly for measuring DC voltage.

[0005] However, due to the actual needs of some projects, a voltage measuring device needs to be installed on the converter valve side to measure the AC component of the voltage on the converter valve side, so as to provide a voltage signal for the neutral point offset protection of the control and protection system. The installation position and voltage of the voltage measuring device at this time are shown in Figure 6.

[0006] Since this voltage measuring device needs to measure AC voltage with a high DC component, neither traditional DC voltage measuring devices nor AC voltage measuring devices are applicable. Summary of the Invention

[0007] To address the aforementioned technical problems, this utility model combines the characteristics of AC voltage measuring devices and DC voltage measuring devices, fully considering the insulation and measurement performance of the equipment under this operating condition, and proposes a device for measuring AC voltage on the valve side of a converter transformer. This device can accurately measure AC voltage in this application scenario, providing a voltage signal for neutral point offset protection in the control and protection system. The device includes:

[0008] The main unit consists of a resistor-capacitor voltage divider, used to divide the superimposed AC and DC voltages;

[0009] The secondary voltage divider unit has a capacitor voltage divider connected in parallel to the output terminal of the resistor-capacitor voltage divider, which is used to isolate the DC component output by the main unit from the DC voltage.

[0010] Furthermore, the resistive-capacitive voltage divider includes:

[0011] Capacitors C1 and C2, resistors R1 and R2; wherein capacitor C1 and resistor R1 are connected in parallel to form the high-voltage section of the RC voltage divider; capacitor C2 and R2 are connected in parallel to form the low-voltage section of the RC voltage divider;

[0012] The high-voltage section and the low-voltage section are connected in series to form the resistive-capacitive voltage divider;

[0013] The output terminal of the resistor-capacitor voltage divider outputs a superimposed AC / DC voltage after voltage division.

[0014] Furthermore, the value of resistor R1 is between 100MΩ and 500MΩ, and it is composed of multiple chip-type high-voltage glass glaze resistors connected in series and parallel.

[0015] Capacitor C1 has an oil-impregnated film-paper composite insulation structure and is composed of multiple capacitors connected in series. Its capacitance ranges from 2nF to 200nF.

[0016] The numerical relationships between R1, C1 and R2, C2 are as follows:

[0017]

[0018] Furthermore, the capacitor divider in the secondary voltage divider section includes capacitors C3 and C4;

[0019] The voltage division ratio of the AC voltage output from the secondary voltage divider section is:

[0020]

[0021] This utility model also provides a device for measuring the AC voltage on the valve side of a converter transformer, comprising:

[0022] The main unit consists of a resistor-capacitor voltage divider, used to divide the superimposed AC and DC voltages;

[0023] The passive filtering unit, consisting of a passive high-pass filter, is used to connect the passive high-pass filter to the output terminal of the resistor-capacitor voltage divider to filter out the DC voltage component output by the main unit.

[0024] Furthermore, the resistive-capacitive voltage divider includes:

[0025] Capacitors C1 and C2, resistors R1 and R2; wherein capacitor C1 and resistor R1 are connected in parallel to form the high-voltage section of the RC voltage divider; capacitor C2 and R2 are connected in parallel to form the low-voltage section of the RC voltage divider;

[0026] The high-voltage section and the low-voltage section are connected in series to form the resistive-capacitive voltage divider;

[0027] The output terminal of the resistor-capacitor voltage divider outputs a superimposed AC / DC voltage after voltage division.

[0028] Furthermore, the value of resistor R1 is between 100MΩ and 500MΩ, and it is composed of multiple chip-type high-voltage glass glaze resistors connected in series and parallel.

[0029] Capacitor C1 has an oil-impregnated film-paper composite insulation structure and is composed of multiple capacitors connected in series. Its capacitance ranges from 2nF to 200nF.

[0030] The numerical relationships between R1, C1 and R2, C2 are as follows:

[0031]

[0032] Furthermore, the passive high-pass filter includes: capacitor C3 and resistor R3;

[0033] If the cutoff frequency of the passive high-pass filter is 10Hz, then the relationship between C3 and R3 is as follows;

[0034]

[0035] Where R3≤1.43kΩ, C2≥100C3.

[0036] This utility model also provides a device for measuring the AC voltage on the valve side of a converter transformer, comprising:

[0037] The main unit consists of a resistor-capacitor voltage divider, used to divide the superimposed AC and DC voltages;

[0038] An active filtering unit, consisting of an active high-pass filter, is used to connect an active high-pass filter to the output terminal of the resistor-capacitor voltage divider to filter out the DC voltage component output by the main unit.

[0039] Furthermore, the resistive-capacitive voltage divider includes:

[0040] Capacitors C1 and C2, resistors R1 and R2; wherein capacitor C1 and resistor R1 are connected in parallel to form the high-voltage section of the RC voltage divider; capacitor C2 and R2 are connected in parallel to form the low-voltage section of the RC voltage divider;

[0041] The high-voltage section and the low-voltage section are connected in series to form the resistive-capacitive voltage divider;

[0042] The output terminal of the resistor-capacitor voltage divider outputs a superimposed AC / DC voltage after voltage division.

[0043] Furthermore, the value of resistor R1 is between 100MΩ and 500MΩ, and it is composed of multiple chip-type high-voltage glass glaze resistors connected in series and parallel.

[0044] Capacitor C1 has an oil-impregnated film-paper composite insulation structure and is composed of multiple capacitors connected in series. Its capacitance ranges from 2nF to 200nF.

[0045] The numerical relationships between R1, C1 and R2, C2 are as follows:

[0046]

[0047] Furthermore, the active high-pass filter includes: capacitor C3, resistor R4, and resistor R. f and operational amplifiers;

[0048] If the cutoff frequency of the active high-pass filter is 10Hz, then the relationship between C3 and R3 is as follows;

[0049]

[0050] The input-output voltage ratio of the active high-pass filter is:

[0051]

[0052] Where V2 is the output voltage, V1 is the input voltage, and R... f The feedback resistor is j, which is the imaginary unit, and ω is the angular frequency.

[0053] If the amplification factor of the active high-pass filter is set to 1, then

[0054]

[0055] At 50Hz, R3, C3, and R f The following relationship must be satisfied:

[0056] ωC3(R f +R3)=1.

[0057] This invention proposes a device for measuring the AC voltage on the converter transformer valve side. It utilizes a resistive-capacitive voltage divider and a secondary voltage divider or high-pass filter. On the one hand, it fully considers the insulation problem of the equipment under AC and DC voltages, and on the other hand, it fully considers the input requirements of the control and protection device, that is, it only measures the AC voltage signal under AC and DC voltages. This solves the problem of measuring the AC voltage on the converter transformer valve side and provides effective support for engineering applications. Attached Figure Description

[0058] Figure 1 is a structural diagram of a device for measuring the AC voltage on the converter valve side provided in an embodiment of the present invention;

[0059] Figure 2 is a structural diagram of another device for measuring AC voltage on the converter valve side provided in an embodiment of the present invention;

[0060] Figure 3 is a structural diagram of another device for measuring AC voltage on the converter valve side provided in an embodiment of the present invention;

[0061] Figure 4 shows the location of the DC measuring device in the DC system provided in the embodiment of this utility model;

[0062] Figure 5 shows the position (VT1) of the converter valve side voltage measuring device provided in this embodiment of the present invention;

[0063] Figure 6 shows the voltage waveform on the converter valve side provided in this embodiment of the present invention. Detailed Implementation

[0064] Many specific details are set forth in the following description to provide a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0065] This invention proposes a device for measuring AC voltage on the valve side of a converter transformer. It utilizes the advantage of a RC voltage divider having a uniform electric field under AC and DC superimposed electric fields. At the same time, it fully considers the characteristic of the measured signal having a high DC voltage component. Through impedance matching, the parameter matching principle of the RC voltage divider is determined, effectively solving the problem of AC voltage measurement on the valve side of the converter transformer.

[0066] To achieve the above objectives, the technical solution of this utility model is as follows:

[0067] This invention proposes a device for measuring the AC voltage on the converter transformer valve side. There are three main implementation schemes. The first scheme is a device using a capacitor voltage divider for secondary voltage division, as shown in Figure 1. It includes two parts: a main unit and a secondary voltage divider unit. The main unit is composed of a resistor-capacitor voltage divider, used to divide the superimposed AC and DC voltages. The secondary voltage divider unit has a capacitor voltage divider connected in parallel to the output terminals of the resistor-capacitor voltage divider, used to isolate the DC component output by the main unit from the DC voltage.

[0068] A resistive-capacitive voltage divider includes:

[0069] Capacitors C1 and C2, resistors R1 and R2; wherein capacitor C1 and resistor R1 are connected in parallel to form the high-voltage section of the RC voltage divider; capacitor C2 and R2 are connected in parallel to form the low-voltage section of the RC voltage divider;

[0070] The high-voltage section and the low-voltage section are connected in series to form the resistive-capacitive voltage divider;

[0071] The output terminal of the resistor-capacitor voltage divider outputs a superimposed AC / DC voltage after voltage division.

[0072] The value of resistor R1 is between 100MΩ and 500MΩ, and it is composed of multiple chip high voltage glass glaze resistors connected in series and parallel.

[0073] Capacitor C1 has an oil-impregnated film-paper composite insulation structure and is composed of multiple capacitors connected in series. Its capacitance ranges from 2nF to 200nF.

[0074] The main unit is an oil-immersed device, filled with capacitor oil.

[0075] The numerical relationships between R1, C1 and R2, C2 are as follows:

[0076]

[0077] Because the signal after the AC / DC superimposed voltage is divided by the RC voltage divider still has a high DC component, this high DC component can affect the insulation of the control and protection device. Therefore...

[0078] A capacitor divider is connected in parallel to the output terminal of the resistor-capacitor voltage divider to isolate the DC voltage. Therefore, the secondary voltage divider section of this device is a resistor-capacitor voltage divider. C3 It is composed of C4.

[0079] The voltage division ratio of the AC voltage output from the secondary voltage divider section is:

[0080]

[0081] The control and protection device has a small PT or resistor divider for secondary voltage division. The secondary voltage division method using the capacitor divider needs to fully consider its load-carrying capacity. Taking a 143kΩ resistor divider as an example, in this case, the value of C1 needs to be around 200nF, and the value of C3 needs to be 200-300nF.

[0082] The second technical solution is a device that uses a passive high-pass filter for DC filtering, and its structure diagram is shown in Figure 2.

[0083] This device is also divided into two parts: a main unit and a passive filtering unit. The main unit consists of a resistor-capacitor voltage divider, used to divide the superimposed AC and DC voltages; the passive filtering unit consists of a passive high-pass filter, used to connect the passive high-pass filter to the output terminal of the resistor-capacitor voltage divider, used to filter out the DC voltage component output by the main unit.

[0084] A resistive-capacitive voltage divider includes:

[0085] Capacitors C1 and C2, resistors R1 and R2; wherein capacitor C1 and resistor R1 are connected in parallel to form the high-voltage section of the RC voltage divider; capacitor C2 and R2 are connected in parallel to form the low-voltage section of the RC voltage divider;

[0086] The high-voltage section and the low-voltage section are connected in series to form the resistive-capacitive voltage divider;

[0087] The output terminal of the resistor-capacitor voltage divider outputs a superimposed AC / DC voltage after voltage division.

[0088] The value of resistor R1 is between 100MΩ and 500MΩ, and it is composed of multiple chip high voltage glass glaze resistors connected in series and parallel.

[0089] Capacitor C1 has an oil-impregnated film-paper composite insulation structure and is composed of multiple capacitors connected in series. Its capacitance ranges from 2nF to 200nF.

[0090] The main unit is an oil-immersed device, filled with capacitor oil.

[0091] The numerical relationships between R1, C1 and R2, C2 are as follows:

[0092]

[0093] The passive high-pass filter includes: capacitor C3 and resistor R3;

[0094] If the cutoff frequency of the passive high-pass filter is 10Hz, then the relationship between C3 and R3 is as follows;

[0095]

[0096] Where R3≤1.43kΩ, C2≥100C3.

[0097] The third technical solution is a device using an active high-pass filter, the structure of which is shown in Figure 3.

[0098] This device is also divided into two parts: a main unit and an active filter unit. The main unit is composed of a resistor-capacitor voltage divider, which is used to divide the superimposed AC and DC voltages. An active high-pass filter is connected to the output terminal of the capacitor voltage divider to filter out the DC voltage component output by the main unit.

[0099] A resistive-capacitive voltage divider includes:

[0100] Capacitors C1 and C2, resistors R1 and R2; wherein capacitor C1 and resistor R1 are connected in parallel to form the high-voltage section of the RC voltage divider; capacitor C2 and R2 are connected in parallel to form the low-voltage section of the RC voltage divider;

[0101] The high-voltage section and the low-voltage section are connected in series to form the resistive-capacitive voltage divider;

[0102] The output terminal of the resistor-capacitor voltage divider outputs a superimposed AC / DC voltage after voltage division.

[0103] The value of resistor R1 is between 100MΩ and 500MΩ, and it is composed of multiple chip-type high voltage glass glaze resistors connected in series and parallel.

[0104] Capacitor C1 has an oil-impregnated film-paper composite insulation structure and is composed of multiple capacitors connected in series. Its capacitance ranges from 2nF to 200nF.

[0105] The main unit is an oil-immersed device, filled with capacitor oil.

[0106] The numerical relationships between R1, C1 and R2, C2 are as follows:

[0107]

[0108] An active high-pass filter includes: capacitor C3, resistor R4, and resistor R. f and operational amplifiers;

[0109] If the cutoff frequency of the active high-pass filter is 10Hz, then the relationship between C3 and R3 is as follows;

[0110]

[0111] The input-output voltage ratio of the active high-pass filter is:

[0112]

[0113] Where V2 is the output voltage, V1 is the input voltage, and R... f The feedback resistor is j, which is the imaginary unit, and ω is the angular frequency.

[0114] Since only the DC voltage component needs to be filtered out, the amplification factor of the active high-pass filter is set to 1.

[0115]

[0116] At 50Hz, R3, C3, and R f The following relationship must be satisfied:

[0117] ωC3(R f +R3)=1.

[0118] This invention proposes a device for measuring the AC voltage on the converter transformer valve side. It utilizes a resistive-capacitive voltage divider and a secondary voltage divider or high-pass filter. On the one hand, it fully considers the insulation problem of the equipment under AC and DC voltages, and on the other hand, it fully considers the input requirements of the control and protection device, that is, it only measures the AC voltage signal under AC and DC voltages. This solves the problem of measuring the AC voltage on the converter transformer valve side and provides effective support for engineering applications.

[0119] Those skilled in the art will understand that embodiments of this invention can be provided as methods, systems, or computer program products. Therefore, this invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0120] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0121] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0122] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this utility model without departing from the spirit and scope of this utility model. Any modifications or equivalent substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A device for measuring the AC voltage on the valve side of a converter transformer, characterized in that, include: The main unit consists of a resistor-capacitor voltage divider, used to divide the superimposed AC and DC voltages; the secondary voltage divider unit has a capacitor voltage divider connected in parallel to the output terminals of the resistor-capacitor voltage divider, used to isolate the DC component output by the main unit from the DC voltage.

2. The apparatus according to claim 1, characterized in that, A resistive-capacitive voltage divider includes: capacitors C1 and C2, and resistors R1 and R2; wherein capacitor C1 and resistor R1 are connected in parallel to form the high-voltage section of the resistive-capacitive voltage divider; capacitor C2 and R2 are connected in parallel to form the low-voltage section of the resistive-capacitive voltage divider; the high-voltage section and the low-voltage section are connected in series to form the resistive-capacitive voltage divider; the output terminal of the resistive-capacitive voltage divider outputs a superimposed AC / DC voltage after voltage division.

3. The apparatus according to claim 2, characterized in that, The resistor R1 has a value between 100MΩ and 500MΩ and is composed of multiple chip-type high-voltage glass enamel resistors connected in series and parallel; the capacitor C1 has an oil-impregnated film-paper composite insulation structure and is composed of multiple capacitors connected in series, with a capacitance between 2nF and 200nF; the numerical relationship between R1, C1 and R2, C2 is as follows: 。 4. The apparatus according to claim 1, characterized in that, The capacitor divider in the secondary voltage divider section includes capacitors C3 and C4; the AC voltage division ratio of the output from the secondary voltage divider section is: 。 5. A device for measuring the AC voltage on the valve side of a converter transformer, characterized in that, include: The main unit, consisting of a resistor-capacitor voltage divider, is used to divide the superimposed AC and DC voltages; the passive filter unit, consisting of a passive high-pass filter, is used to connect the passive high-pass filter to the output terminal of the resistor-capacitor voltage divider to filter out the DC voltage component output by the main unit.

6. The apparatus according to claim 5, characterized in that, A resistive-capacitive voltage divider includes: capacitors C1 and C2, and resistors R1 and R2; wherein capacitor C1 and resistor R1 are connected in parallel to form the high-voltage section of the resistive-capacitive voltage divider; capacitor C2 and R2 are connected in parallel to form the low-voltage section of the resistive-capacitive voltage divider; the high-voltage section and the low-voltage section are connected in series to form the resistive-capacitive voltage divider; the output terminal of the resistive-capacitive voltage divider outputs a superimposed AC / DC voltage after voltage division.

7. The apparatus according to claim 6, characterized in that, The resistor R1 has a value between 100MΩ and 500MΩ and is composed of multiple chip-type high-voltage glass enamel resistors connected in series and parallel; the capacitor C1 has an oil-impregnated film-paper composite insulation structure and is composed of multiple capacitors connected in series, with a capacitance between 2nF and 200nF; the numerical relationship between R1, C1 and R2, C2 is as follows: 。 8. The apparatus according to claim 5, characterized in that, A passive high-pass filter includes a capacitor C3 and a resistor R3. The cutoff frequency of the passive high-pass filter is 10Hz. The relationship between C3 and R3 is as follows. Where R3≤1.43kΩ, C2≥100C3.

9. A device for measuring the AC voltage on the valve side of a converter transformer, characterized in that, include: The main unit consists of a resistor-capacitor voltage divider, used to divide the superimposed AC and DC voltages; An active filtering unit, consisting of an active high-pass filter, is used to connect an active high-pass filter to the output terminal of the resistor-capacitor voltage divider to filter out the DC voltage component output by the main unit.

10. The apparatus according to claim 9, characterized in that, A resistive-capacitive voltage divider includes: capacitors C1 and C2, and resistors R1 and R2; wherein capacitor C1 and resistor R1 are connected in parallel to form the high-voltage section of the resistive-capacitive voltage divider; capacitor C2 and R2 are connected in parallel to form the low-voltage section of the resistive-capacitive voltage divider; the high-voltage section and the low-voltage section are connected in series to form the resistive-capacitive voltage divider; the output terminal of the resistive-capacitive voltage divider outputs a superimposed AC / DC voltage after voltage division.

11. The apparatus according to claim 10, characterized in that, The resistor R1 has a value between 100MΩ and 500MΩ and is composed of multiple chip-type high-voltage glass enamel resistors connected in series and parallel; the capacitor C1 has an oil-impregnated film-paper composite insulation structure and is composed of multiple capacitors connected in series, with a capacitance between 2nF and 200nF; the numerical relationships between R1, C1 and R2, C2 are as follows: 。 12. The apparatus according to claim 9, characterized in that, An active high-pass filter includes: capacitor C3, resistor R4, and resistor R. f And operational amplifier; the cutoff frequency of the active high-pass filter is 10Hz, then the relationship between C3 and R3 is as follows; The input-output voltage ratio of the active high-pass filter is: Where V2 is the output voltage and V1 is the input voltage. For feedback resistor, The imaginary unit, The angular frequency is denoted by 1; if the amplification factor of the active high-pass filter is set to 1, then... At 50Hz, R3, C3, and R f The following relationship must be satisfied: 。

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