CN214226650U

CN214226650U - Harmonic elimination resistor for gear type electromagnetic voltage transformer

Info

Publication number: CN214226650U
Application number: CN202120359567.3U
Authority: CN
Inventors: 朱子怡; 朱妍; 朱翔
Original assignee: Nanjing Greenly Technology Co ltd
Current assignee: Nanjing Greenly Technology Co ltd
Priority date: 2021-02-06
Filing date: 2021-02-06
Publication date: 2021-09-17
Anticipated expiration: 2031-02-06

Abstract

The utility model discloses a harmonic elimination resistor of gear type electromagnetic type voltage transformer, change neutral point, insulating end cover, resistive element, screw rod and ground connection base including connecing to press, the one end dress of resistive element is on the ground connection base, connect to press to change the neutral point and be connected with the other end of resistive element, insulating end cover cup joints on connecing to press to change the neutral point, through screw rod fixed connection between ground connection base and the insulating end cover, the resistive element is the gear type. The utility model discloses the resistive element is the gear form, and the insulating strength of gear type harmonic elimination resistor can with the weak insulation phase-match of electromagnetic type voltage transformer neutral point, is applicable to all insulation and weak insulation voltage transformer, need not to distinguish all insulation and weak insulation voltage transformer, has good popularization and application and worth, provides reliable inspection means for the safe operation of electric wire netting, also brings obvious economic benefits for the electric wire netting simultaneously, has fine popularization and application and worth.

Description

Harmonic elimination resistor for gear type electromagnetic voltage transformer

Technical Field

The utility model relates to an electromagnetic type voltage transformer primary winding neutral point that electric power system used can play damping effect's harmonic elimination ware technical field between the ground, especially relates to a gear type electromagnetic type voltage transformer harmonic elimination resistor.

Background

When the system operates or fails, the nonlinear inductance elements such as transformers and transformers containing iron core elements are connected in series with the capacitor in the system to cause ferroresonance, which endangers the safe operation of the power system. In an indirect grounding system with an ungrounded neutral point, ferromagnetic resonance overvoltage caused by an electromagnetic voltage transformer is common and is internal overvoltage causing more accidents, and when the overvoltage is light, a fuse wire of the voltage transformer is fused, and when the overvoltage is heavy, the voltage transformer is burnt, and even a porcelain insulator and a lightning arrester are burnt, so that the system is stopped. Under the action of a certain power supply, the mutual inductor can generate a series resonance phenomenon, so that serious resonance overvoltage occurs in a system.

In order to prevent the mutual inductor from generating ferromagnetic resonance, limit overlarge inrush current to burn the mutual inductor and fuse the protective fuse of the mutual inductor, a nonlinear damping resistor with proper resistance and capacity can be connected between the neutral point of the primary winding of the electromagnetic voltage mutual inductor and the ground, and the nonlinear damping resistor is called as a resonance elimination resistor. However, when the fully-insulated and weakly-insulated electromagnetic voltage transformers are applied, harmonic elimination resistors with different specifications and types need to be selected correspondingly, so that the procedures of installation, maintenance and the like become complicated and inefficient, and therefore, a universal harmonic elimination resistor which does not need to distinguish the fully-insulated and weakly-insulated voltage transformers is urgently needed.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a harmonic elimination resistor of gear type electromagnetic type voltage transformer to solve the problem that proposes among the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme: the harmonic elimination resistor comprises a voltage-variable neutral point, an insulating end cover, a resistor body, a screw and a grounding base, wherein one end of the resistor body is arranged on the grounding base, the voltage-variable neutral point is connected with the other end of the resistor body, the insulating end cover is sleeved on the voltage-variable neutral point, the grounding base is fixedly connected with the insulating end cover through the screw, and the resistor body is of a gear type.

Further, the resistor body has a solid cross section.

Further, a metal sheet is interposed between the proximal end portions of the adjacent resistors.

Furthermore, the screws are distributed in grooves in the outer edge of the resistor gear.

Furthermore, the grounding base is provided with 1 mounting hole.

Further, the resistor system is made of a nonlinear material.

Compared with the prior art, the utility model, the beneficial effect who has is:

the utility model discloses the resistive element is gear form, compares with circular, and resistance surface area increases more than 50%, and heat radiating area increases, and corresponding capacity also increases, under the harsher fault condition of electric wire netting, for example long-time intermittent type ground connection, the capacity of gear type harmonic elimination resistor satisfies the requirement completely; the insulating strength of the gear type harmonic elimination resistor can be matched with the neutral point weak insulation of the electromagnetic voltage transformer, the gear type harmonic elimination resistor is suitable for all-insulated and weak-insulated voltage transformers, the all-insulated and weak-insulated voltage transformers do not need to be distinguished, good popularization and application values are achieved, a reliable detection means is provided for safe operation of a power grid, meanwhile, obvious economic benefits are brought to the power grid, and the gear type harmonic elimination resistor has good popularization and application values.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of the structure of the present invention in the direction of A-A;

in the figure: 1. voltage-connected variable neutral points; 2. an insulating end cap; 3. a resistor body; 4. a screw; 5. a ground base; 6. a metal sheet; 7. and (7) installing holes.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. Also, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element or "connected" to the other element through a third element.

As shown in fig. 1-2, a gear-type electromagnetic voltage transformer harmonic elimination resistor comprises a voltage-receiving variable neutral point 1, an insulating end cover 2, a resistor body 3, a screw rod 4 and a grounding base 5, wherein one end of the resistor body 3 is installed on the grounding base 5, 1 installation hole 7 is further formed in the grounding base 5, the voltage-receiving variable neutral point 1 is connected with the other end of the resistor body 3, the insulating end cover 2 is sleeved on the voltage-receiving variable neutral point 1, the grounding base 5 is fixedly connected with the insulating end cover 2 through the screw rod 4, the screw rod 4 is distributed in a groove in the outer edge of a gear of the resistor body 3, and the resistor body 3 is of a solid gear type and is made of a nonlinear material.

The section of the resistor body 3 is in a gear shape, compared with a circular shape, the surface area of the resistor is increased by more than 50%, the heat dissipation area is increased, the corresponding capacity is also increased, under the most harsh fault condition of a power grid, such as long-time intermittent grounding, the capacity of the gear-shaped resonance elimination resistor completely meets the requirement, and a metal sheet 6 is clamped between the near end parts of the adjacent resistor bodies 3; the surface area of the resistor body 3 is increased, the corresponding capacity is increased, the height of the resistor body can be reduced, the overall height of the resonance elimination resistor can also be reduced, and the installation in an electromagnetic voltage transformer cabinet with limited space is facilitated; the resonance elimination resistor can meet the requirements of various power grid voltage grades conventionally such as: 6kV, 10kV, 20kV and 35kV, and special voltage grades can be customized according to requirements; the insulating strength of the gear-shaped harmonic elimination resistor can be matched with the weak insulation of the neutral point of the electromagnetic voltage transformer, the gear-shaped harmonic elimination resistor is suitable for all-insulated and weak-insulated voltage transformers, the all-insulated and weak-insulated voltage transformers do not need to be distinguished, good popularization and application values are achieved, a reliable detection means is provided for safe operation of a power grid, meanwhile, obvious economic benefits are brought to the power grid, and the gear-shaped harmonic elimination resistor has good popularization and application values.

The resistance value of the resonance elimination resistor in the embodiment can be calibrated by the value of the power frequency current 10 mA. The resistance system of the harmonic elimination resistor in the embodiment is made of nonlinear materials, and the resistance value of the harmonic elimination resistor is different according to different currents passing through the harmonic elimination resistor. The calibration basis is as follows: most of the fundamental wave values of the exciting current with the voltage change under the rated line voltage are about 10mA, and when the voltage change does not generate ferromagnetic resonance when R10mA/Xm is more than or equal to 0.06 through the ratio of the value R10mA of 10mA to the exciting reactance Xm of the single-phase voltage change under the rated line voltage; the voltage-variable voltage-current characteristic of the resonance elimination resistor is nonlinear because the voltage-variable voltage-current characteristic is nonlinear, and when the ratio of the resistance value R10mA of the resonance elimination resistor 10mA to the voltage-variable rated excitation reactance Xm is not less than 0.06, if the value of the resonance elimination resistor at other current is required to meet the condition of not less than 0.06, the voltage-current characteristic of the resonance elimination resistor is required to be basically consistent with the voltage-variable voltage-current characteristic, so the nonlinear coefficient of the resonance elimination resistor is required to be within a certain range. The utility model discloses a value when harmonic elimination resistor 1mA marks harmonic elimination resistor's nonlinear characteristic, calculates harmonic elimination resistor's nonlinear coefficient with 1mA and 10 mA's magnitude of voltage.

In the embodiment, when the power grid normally operates and the single-phase metal is grounded, the current flowing through the resonance elimination resistor is below 20mA, and the capacity requirement of the resonance elimination resistor is not large. The operating regime requiring a large capacity for the detuning resistor is a continuous single-phase arc ground (intermittent ground), in which case an inrush current of several hundred milliamperes flows through the detuning resistor and lasts for a long time. The utility model discloses a 2 hours mark the thermal capacity of harmonic elimination resistor through 200mA power frequency current, and harmonic elimination resistor takes place under the extreme condition that arc light ground connection reaches 2 hours at the electric wire netting, also can not damage.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.

Claims

1. The utility model provides a harmonic elimination resistor of gear type electromagnetic type voltage transformer which characterized in that: including joint pressure change neutral point (1), insulating end cover (2), resistive element (3), screw rod (4) and ground connection base (5), the one end dress of resistive element (3) is on ground connection base (5), joint pressure change neutral point (1) is connected with the other end of resistive element (3), and insulating end cover (2) cup joint and connect pressure change neutral point (1), through screw rod (4) fixed connection between ground connection base (5) and insulating end cover (2), resistive element (3) are the gear type.

2. The harmonic elimination resistor of the gear-type electromagnetic voltage transformer according to claim 1, characterized in that: the section of the resistor body (3) is solid.

3. A harmonic elimination resistor according to claim 1 or 2, characterized in that: a metal sheet (6) is interposed between the proximal end portions of the adjacent resistors (3).

4. The harmonic elimination resistor of the gear-type electromagnetic voltage transformer according to claim 1, characterized in that: the screw rods (4) are distributed in grooves in the outer edge of the gear of the resistor body (3).

5. The harmonic elimination resistor of the gear-type electromagnetic voltage transformer according to claim 1, characterized in that: and 1 mounting hole (7) is formed in the grounding base (5).

6. A harmonic elimination resistor according to claim 1 or 2, characterized in that: the resistor body (3) is made of a nonlinear material.