CN113035507A

CN113035507A - Voltage transformer for direct current GIS

Info

Publication number: CN113035507A
Application number: CN202110437290.6A
Authority: CN
Inventors: 董巍; 孙泽来; 庞辉; 高冲; 王航; 王朝华
Original assignee: State Grid Corp of China SGCC; Global Energy Interconnection Research Institute; State Grid Henan Electric Power Co Ltd
Current assignee: State Grid Corp of China SGCC; Global Energy Interconnection Research Institute; State Grid Henan Electric Power Co Ltd
Priority date: 2021-04-22
Filing date: 2021-04-22
Publication date: 2021-06-25

Abstract

The invention discloses a voltage transformer for a direct current GIS, which comprises: the shell comprises a first air chamber and a second air chamber which are adjacently arranged; the first air chamber is filled with positive-pressure insulating gas, and the second air chamber is filled with normal-pressure gas; the resistance-capacitance voltage divider comprises a high-voltage arm and a low-voltage arm which are connected with each other; the high pressure arm is disposed in the first air chamber and the low pressure arm is disposed in the second air chamber; the high-voltage arm comprises a plurality of stages of resistance-capacitance units which are connected in series. In the embodiment of the invention, as the capacitor in the resistance-capacitance voltage divider has the characteristic of quick shock response and the resistor has the characteristic of damped oscillation, the voltage transformer in the embodiment can measure high-frequency signals. And due to the steady-state voltage division characteristic of the resistor in the resistance-capacitance unit and the high time constant of the resistance-capacitance circuit in the resistance-capacitance unit, the low-frequency signal and the direct-current signal can be measured.

Description

Voltage transformer for direct current GIS

Technical Field

The invention relates to the technical field of power systems, in particular to a voltage transformer for a direct current GIS.

Background

The gas-insulated metal-enclosed switchgear is a metal-enclosed switchgear and a control device, at least a part of which uses a gas above atmospheric pressure as an insulating medium. Gis (gas INSULATED switchgear) is a short term for gas INSULATED metal enclosed switchgear. At present, with the development of high-voltage direct-current power transmission and transformation technologies, a direct-current GIS becomes an optimal technical route in a transformer substation, a converter station and a conversion station among different transmission media due to the characteristics of small occupied space, high reliability and strong interchangeability.

Because the electromagnetic transformer is only suitable for measuring power frequency signals, the capacitor voltage transformer can measure voltage with higher frequency, but is not suitable for measuring direct current voltage due to smaller time constant.

Therefore, no effective and mature means exists at present when the voltage of the direct current GIS is measured.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is the problem that the voltage measurement of the direct current GIS cannot be carried out in the prior art. Therefore, the voltage transformer for the direct current GIS is provided.

In order to achieve the above object, an embodiment of the present invention provides a voltage transformer for a dc GIS, where the voltage transformer includes: the shell comprises a first air chamber and a second air chamber which are adjacently arranged; the first air chamber is filled with positive-pressure insulating gas, and the second air chamber is filled with normal-pressure gas; the resistance-capacitance voltage divider comprises a high-voltage arm and a low-voltage arm which are connected with each other; the high pressure arm is disposed in the first air chamber and the low pressure arm is disposed in the second air chamber; the high-voltage arm comprises a plurality of stages of resistance-capacitance units which are connected in series.

Optionally, both ends of the resistance-capacitance unit are respectively connected with a metal flange.

Optionally, a voltage grading and shielding structure is arranged on the metal flange.

Optionally, the grading shield structure is a grading ring.

Optionally, the grading ring increases in size gradually in a direction from the high pressure arm toward the low pressure arm.

Optionally, a first connecting piece is arranged at one end of the first air chamber far away from the second air chamber, and a second connecting piece is arranged at one end of the first air chamber close to the second air chamber; the first end of the high-voltage arm is connected with the first connecting piece, and the second end of the high-voltage arm is connected with the low-voltage arm through the second connecting piece.

Optionally, the first connector comprises: the first insulating piece is arranged at one end of the first air chamber far away from the second air chamber; the first insulator is adapted to seal a first end of the first plenum; the first contact base is arranged on the first insulating part; the first contact base is connected with the first end of the high-voltage arm; a conductive rod disposed in the primary system; the conductive rod is connected with the first contact base through the first insulating piece.

Optionally, the second connector comprises: the second insulating part is arranged at one end of the first air chamber close to the second air chamber; the second insulator is suitable for isolating the first air chamber and the second air chamber; the second contact base is arranged on the second insulating part; one end of the second contact base is connected with the second end of the high-voltage arm, and the other end of the second contact base is connected with the low-voltage arm.

Optionally, the voltage transformer further comprises: the signal processing device is arranged in the second air chamber; the signal processing device is connected with the low-voltage arm; the signal processing device is used for converting an input electric signal into an optical signal to be output, and the control system is simultaneously connected with the signal processing device and the secondary system.

Optionally, the low-voltage arm is provided with the resistance-capacitance unit.

Compared with the prior art, the technical scheme of the invention has the following advantages:

1. the embodiment of the invention provides a voltage transformer for a direct current GIS, which comprises: the shell comprises a first air chamber and a second air chamber which are adjacently arranged; the first air chamber is filled with positive-pressure insulating gas, and the second air chamber is filled with normal-pressure gas; the resistance-capacitance voltage divider comprises a high-voltage arm and a low-voltage arm which are connected with each other; the high pressure arm is disposed in the first air chamber and the low pressure arm is disposed in the second air chamber; the high-voltage arm comprises a plurality of stages of resistance-capacitance units which are connected in series.

In the embodiment of the invention, as the capacitor in the resistance-capacitance voltage divider has the characteristic of quick shock response and the resistor has the characteristic of damped oscillation, the voltage transformer in the embodiment can measure high-frequency signals. And due to the steady-state voltage division characteristic of the resistor in the resistance-capacitance unit and the high time constant of the resistance-capacitance circuit in the resistance-capacitance unit, the low-frequency signal and the direct-current signal can be measured.

2. The conventional transformer sleeve is made of insulating materials, and the stray capacitance to the ground is the direct capacitance between the component and the ground. Because the shell of the voltage transformer in the embodiment of the invention is made of metal and is at the ground potential, the distance between the shell and the ground is greatly reduced, and the stray capacitance to the ground is increased. And the current leakage caused by the stray capacitance and the reduction effect on the steep wave caused by the stray parameter jointly cause that the partial pressure of the resistance-capacitance unit is gradually reduced in the direction from the high-voltage arm to the low-voltage arm. According to the embodiment of the invention, the size of the grading ring is gradually increased in the direction from the high-voltage arm to the low-voltage arm, so that the grading ring has different sizes, and the uneven voltage division of the resistance-capacitance unit can be compensated, thereby realizing the balance of voltage distribution and the optimization of an electric field, and improving the insulation reliability. In addition, the influence of stray capacitance on measurement errors is inhibited by a method of compensating and adjusting the distance between the grading ring and the shell and the distance between the grading ring and the shell, and the measurement precision is further improved.

3. According to the invention, the low-voltage arm and the signal processing device are arranged in the second air chamber, and the second air chamber is filled with normal-pressure gas, so that the measurement wiring, maintenance and other work are facilitated.

4. According to the invention, the signal processing device is arranged in the second air chamber and is connected with the low-voltage arm, so that long-distance signal transmission is not carried out by using a long cable, and an electric signal is not sent to a remote secondary system for signal processing, thereby effectively avoiding the threat of TEV and EMI common in GIS to the safety of measuring equipment and the influence of measuring precision.

5. According to the invention, the resistance-capacitance unit of the low-voltage arm is selected from devices with the same process and parameters as those of the high-voltage arm, so that the consistency of the response characteristics of the high-voltage arm and the low-voltage arm and the synchronization of temperature deviation can be ensured, and the measurement accuracy is ensured.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for a worker of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

Fig. 1 is a schematic view of an overall structure of a voltage transformer according to an embodiment of the present invention.

Reference numerals:

1. a housing; 2. a high pressure arm; 3. a low pressure arm; 4. a metal flange; 5. a voltage-sharing shielding structure; 6. a first contact base; 7. a first insulating member; 8. a second contact base; 9. a second insulating member; 10. a signal processing device; 11. a resistance-capacitance unit; 12. a first air chamber; 13. a second air chamber.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a worker skilled in the art without creative efforts based on the embodiments of the present invention, belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meanings of the above terms in the present invention can be understood in specific cases by a worker of ordinary skill in the art.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The gas-insulated metal-enclosed switchgear is a metal-enclosed switchgear and a control device, at least a part of which uses a gas above atmospheric pressure as an insulating medium. Gis (gas INSULATED switchgear) is a short term for gas INSULATED metal enclosed switchgear. At present, with the development of high-voltage direct-current power transmission and transformation technologies, a direct-current GIS becomes an optimal technical route in a transformer substation, a converter station and a conversion station among different transmission media due to the characteristics of small occupied space, high reliability and strong interchangeability. Because the electromagnetic transformer is only suitable for measuring power frequency signals, the capacitor voltage transformer can measure voltage with higher frequency, but is not suitable for measuring direct current voltage due to smaller time constant. Therefore, no effective and mature means exists at present when the voltage of the direct current GIS is measured.

Example 1

As shown in fig. 1, an embodiment of the present invention provides a voltage transformer for a dc GIS, where the voltage transformer includes: the casing 1, the resistance-capacitance voltage divider and the resistance-capacitance unit 11.

The housing 1 comprises a first air chamber 12 and a second air chamber 13 which are adjacently arranged, wherein the first air chamber 12 is filled with positive pressure insulating gas, and the second air chamber 13 is filled with normal pressure gas. The resistance-capacitance voltage divider comprises a high-pressure arm 2 and a low-pressure arm 3 which are connected with each other, wherein the high-pressure arm 2 is transversely arranged in the first air chamber 12, and the low-pressure arm 3 is transversely arranged in the second air chamber 13. And a plurality of stages of resistance-capacitance units 11 which are mutually connected in series are arranged on the high-voltage arm 2. Specifically, as to the number of the resistance-capacitance units 11, a person skilled in the art may adjust the number according to actual situations, for example, the number may be 7 levels of resistance-capacitance units 11 connected in series, and this embodiment is merely an example, and is not limited to this embodiment, and the related technical effects may be achieved.

In the embodiment of the invention, as the capacitor in the resistance-capacitance voltage divider has the characteristic of quick shock response and the resistor has the characteristic of damped oscillation, the voltage transformer in the embodiment can measure high-frequency signals. Moreover, due to the steady-state voltage division characteristic of the resistor in the resistance-capacitance unit 11 and the high time constant of the resistance-capacitance circuit in the resistance-capacitance unit 11, the low-frequency signal and the direct-current signal can be measured.

Since the conventional transformer bushing is an insulating material, the stray capacitance to ground is the capacitance between the component and ground. The shell 1 of the voltage transformer in the embodiment of the invention is made of metal, and the shell 1 is the ground potential, which means that the distance between the shell 1 and the ground is greatly reduced, so that the stray capacitance to the ground is increased. The current leakage caused by stray capacitance and the reduction effect on steep waves caused by stray parameters jointly cause that the partial voltage of the resistance-capacitance unit 11 is gradually reduced in the direction from the high-voltage arm 2 to the low-voltage arm 3.

In some embodiments of the present invention, two ends of the resistance-capacitance unit 11 are respectively connected with the metal flange 4. And a voltage-sharing shielding structure 5 is arranged on the metal flange 4. The grading and shielding structure 5 may be a grading ring. In the direction from the high-voltage arm 2 to the low-voltage arm 3, the size of the grading ring gradually increases.

With such arrangement, in the embodiment of the present invention, the size of the grading ring is gradually increased in the direction from the high-voltage arm 2 to the low-voltage arm 3, so that the grading ring has different sizes, and can compensate for uneven voltage division of the resistance-capacitance unit 11, thereby realizing balance of voltage distribution and optimization of an electric field, and improving insulation reliability. In addition, the influence of stray capacitance on measurement errors is inhibited by a method of compensating and adjusting the distance between the grading ring and the shell 1 and the distance between the grading ring and the shell, and the measurement precision is further improved.

Optionally, in some embodiments of the present invention, the first air chamber 12 is provided with a first connecting piece at an end far away from the second air chamber 13, and the first air chamber 12 is provided with a second connecting piece at an end near to the second air chamber 13. The first end of the high-voltage arm 2 is connected with the first connecting piece, and the second end of the high-voltage arm 2 is connected with the low-voltage arm 3 through the second connecting piece.

In particular, the first connection member comprises a first insulating member 7, a first contact socket 6 and a conductive rod. A first insulator 7 is arranged at an end of the first gas chamber 12 remote from the second gas chamber 13, the first insulator 7 being adapted to seal a first end of the first gas chamber 12. A first contact socket 6 is arranged on the first insulator 7, which first contact socket 6 is connected to a first end of the high voltage arm 2. A conducting rod is arranged in the primary system, said conducting rod being connected to said first contact socket 6 via said first insulating member 7.

In particular, the second connection comprises a second insulator 9 and a second contact seat 8. A second insulating member 9 is disposed at an end of the first air chamber 12 close to the second air chamber 13, the second insulating member 9 being adapted to isolate the first air chamber 12 from the second air chamber 13. The second contact base 8 is arranged on the second insulating member 9, one end of the second contact base 8 is connected with the second end of the high-voltage arm 2, and the other end is connected with the low-voltage arm 3.

The first insulator 7 and the second insulator 9 are used for supporting the high-voltage arm 2 and the low-voltage arm 3, and can also play roles of insulation and air chamber isolation. Of course, in this embodiment, a person skilled in the art may change the materials of the first insulating member 7 and the second insulating member 9 according to actual situations, and the material of this embodiment is not limited, and the same technical effects can be achieved.

Optionally, in some embodiments of the present invention, the voltage transformer further includes a signal processing device 10, the signal processing device 10 is disposed in the second gas chamber 13, and the signal processing device 10 is connected to the low-voltage arm 3. The signal processing device 10 is used for converting an input electric signal into an optical signal and outputting the optical signal, and the control system is simultaneously connected with the signal processing device 10 and the secondary system.

So configured, the present invention facilitates the work of measurement wiring, maintenance, etc. by disposing the low-pressure arm 3 and the signal processing device 10 in the second air chamber 13, and the second air chamber 13 is filled with the normal pressure gas. In addition, the signal processing device 10 is arranged in the second air chamber 13, and the signal processing device 10 is connected with the low-voltage arm 3, so that long cables are not used for long-distance signal transmission, and electric signals are not transmitted to a far-end secondary system for signal processing, so that the danger of common TEV and EMI in the GIS on the safety of measuring equipment and the influence of common TEV and EMI on the measuring precision are effectively avoided.

Optionally, in some embodiments of the present invention, the resistance-capacitance unit 11 is disposed on the low-voltage arm 3. According to the invention, the resistance-capacitance unit 11 of the low-voltage arm 3 is selected from devices with the same process and parameters as those of the high-voltage arm 2, so that the consistency of the response characteristics of the high-voltage arm 2 and the low-voltage arm 3 and the synchronization of temperature deviation can be ensured, and the measurement accuracy is ensured.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Variations and modifications in other variations may occur to those skilled in the art based upon the foregoing description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims

1. A voltage transformer for a direct current GIS, comprising:

the air conditioner comprises a shell (1) and a shell, wherein the shell comprises a first air chamber (12) and a second air chamber (13) which are adjacently arranged; the first air chamber (12) is filled with positive pressure insulating gas, and the second air chamber (13) is filled with normal pressure gas;

the resistance-capacitance voltage divider comprises a high-voltage arm (2) and a low-voltage arm (3) which are connected with each other; the high-pressure arm (2) is arranged in the first air chamber (12) and the low-pressure arm (3) is arranged in the second air chamber (13);

the high-voltage arm (2) comprises a plurality of stages of resistance-capacitance units (11) which are connected in series.

2. The voltage transformer according to claim 1, characterized in that both ends of the resistance-capacitance unit (11) are connected with metal flanges (4), respectively.

3. The voltage transformer according to claim 2, characterized in that a voltage grading shield (5) is provided on said metal flange (4).

4. A voltage transformer according to claim 3, characterized in that the grading shield structure (5) is a grading ring.

5. A voltage transformer according to claim 4, characterized in that the grading ring increases in size gradually in the direction of the high-voltage arm (2) towards the low-voltage arm (3).

6. The voltage transformer according to any of the claims 1-5, characterized in that the first air chamber (12) is provided with a first connection at an end remote from the second air chamber (13), and that the first air chamber (12) is provided with a second connection at an end close to the second air chamber (13); the first end of the high-voltage arm (2) is connected with the first connecting piece, and the second end of the high-voltage arm (2) is connected with the low-voltage arm (3) through the second connecting piece.

7. The voltage transformer of claim 6, wherein the first connector comprises:

a first insulating piece (7) arranged at one end of the first air chamber (12) far away from the second air chamber (13); the first insulator (7) is adapted to seal a first end of the first gas chamber (12);

a first contact seat (6) arranged on the first insulator (7); the first contact base (6) is connected with the first end of the high-voltage arm (2);

a conductive rod disposed in the primary system; the conducting rod is connected with the first contact seat (6) through the first insulating piece (7).

8. The voltage transformer of claim 6, wherein the second connector comprises:

a second insulating member (9) disposed at an end of the first air chamber (12) adjacent to the second air chamber (13); the second insulator (9) is adapted to isolate the first and second gas chambers (12, 13);

a second contact seat (8) arranged on the second insulating member (9); one end of the second contact seat (8) is connected with the second end of the high-voltage arm (2), and the other end of the second contact seat is connected with the low-voltage arm (3).

9. The voltage transformer according to any one of claims 1 to 5, further comprising:

a signal processing device (10) arranged in the second gas chamber (13); the signal processing device (10) is connected with the low-voltage arm (3); the signal processing device (10) is used for converting input electric signals into optical signals to be output, and the control system is simultaneously connected with the signal processing device (10) and the secondary system.

10. Voltage transformer according to any of claims 1-5, characterized in that the low voltage arm (3) is provided with the RC unit (11).