CN201812667U - Electronic current and voltage combined transformer - Google Patents

Abstract

The utility model discloses an electronic current-voltage combination transformer, which comprises a tank body, two air-core coils, two LPCTs, two capacitor pressure divider rings, a sealed terminal board, a remote module, a box body, two transfer flanges, a primary Conductor and two pot insulators; the tank body has an opening, the air-core coils are fixed on both sides of the tank body, and the LPCT is also fixed on both sides of the tank body; two capacitor pressure divider rings are respectively set on the upper and lower sides of the tank body Both ends; the box body is fixed on the top of the tank body and forms a channel corresponding to the opening of the tank body, and the sealed terminal board is set in the box body to block the opening of the tank body, and the remote module is also set outside the sealed terminal board in the box body The transfer flanges are respectively arranged on both sides of the tank body, and a basin-type insulator is respectively fixed at the ends, and the two ends of the primary conductor are respectively fixed with the two basin-type insulators, and are located between the two capacitor voltage divider rings. This combined transformer can simultaneously have the functions of a current transformer and a voltage transformer, and has high working reliability.

Description

An electronic combined current and voltage transformer

technical field

The utility model belongs to the field of high-voltage electrical appliances for power transmission and transformation equipment, and relates to a high-voltage electronic current-voltage combined transformer, in particular to an electronic current-voltage combined transformer that can be used in 66kV～750kV GIS (or HGIS). It is suitable for energy metering, relay protection and power monitoring in GIS or HGIS substations of 66kV, 110kV, 220kV, 330kV, 500kV and 750kV voltage level grids.

Background technique

GIS (Gas Insulated Switchgear, Gas Insulated Switchgear) is a high-voltage combined electrical appliance that seals circuit breakers, isolation/grounding switches, current/voltage transformers, busbars and other components required for power transmission and transformation in a gas-insulated metal casing. HGIS (Hybrid Gas Insulated Switchgear) is a high-voltage switchgear between GIS and AIS. GIS and HGIS have the characteristics of compact structure, small footprint, convenient installation, reliable operation, and maintenance-free. At present, the current transformers and voltage transformers used in GIS and HGIS are all electromagnetic transformers. With the increase of voltage level, electromagnetic current transformers and voltage transformers can no longer adapt to the development of power systems due to their inherent defects. Specifically reflected in:

(1) The manufacturing difficulty, process, cost, volume and weight of electromagnetic transformers will double with the increase of voltage level, and the insulation properties are not good, and the ability to withstand lightning impulse voltage and operating impulse voltage is poor;

(2) The nonlinearity of the magnetization curve of the iron core leads to a small dynamic range of the current transformer, and the current transformer is easy to be saturated under the action of a large current, especially a fault current containing a decaying DC component;

(3) The voltage transformer is prone to ferromagnetic resonance;

(4) The secondary open circuit of the current transformer and the secondary short circuit of the voltage transformer will bring harm to equipment and personnel;

(5) The error of the transformer is related to the load, and the load change may cause the error of the transformer to be out of tolerance;

(6) The current transformer and voltage transformer cannot be combined into one, and the application is not flexible;

(7) The output of the electromagnetic transformer cannot directly interface with digital secondary equipment, and cannot meet the needs of the development of digital substations.

At present, GIS electronic current transformers based on air-core coils and LPCT have been used in engineering applications, but GIS electronic voltage transformers are still realized by conventional voltage transformers plus local data acquisition. On the one hand, this method cannot solve the problem of conventional voltage transformers. The transformer is prone to shortcomings such as ferromagnetic resonance, and it cannot realize the combined current and voltage transformer, which cannot meet the development needs of digital substations.

Based on the foregoing analysis, the designer devoted himself to the development of a current-voltage combined transformer structure, and this case arose from it.

Utility model content

The main purpose of the utility model is to provide an electronic combined current and voltage transformer, which can simultaneously have the functions of a current transformer and a voltage transformer, and has high working reliability.

In order to achieve the above object, the solution of the present utility model is:

An electronic current-voltage combination transformer, including a tank body, two air-core coils, two LPCTs, two capacitor voltage divider rings, a sealed terminal board, a remote module, a box body, two transfer flanges, a The primary conductor and the two pot insulators; wherein, the tank body has an opening, and the air-core coils for sensing the current signal for protection are respectively fixed on both sides of the tank body, and the LPCT for sensing the current signal for measurement is also respectively Fixed on both sides of the tank; two capacitive pressure divider rings are respectively set at the upper and lower ends of the inside of the tank; the tank is fixed on the top of the tank, and forms a channel through the upper and lower corresponding to the opening of the tank, and the sealed terminal board is set The passage position in the box body, and block the opening of the tank body, the remote module is also set in the box body, and is located outside the sealed terminal board; two adapter flanges are respectively set on both sides of the tank body, and each turn A pot insulator is respectively fixed at the end of the connecting flange, and the two ends of the primary conductor are respectively fixed with the two pot insulators, and the primary conductor is located between the two capacitive voltage divider rings.

Rectangular grooves are formed on the left and right sides of the tank body, and the air-core coil and LPCT are fixed in the rectangular grooves.

After adopting the above scheme, the utility model has the following characteristics:

(1) The utility model utilizes the air-core coil and LPCT to sense the primary current, utilizes the coaxial capacitive voltage divider to sense the primary voltage, utilizes the remote module to collect the output signal of the current/voltage sensor nearby, and utilizes the optical fiber to transmit the signal, the structure and The process is simple, the cost is low, and the volume and weight are only 1/4 of the conventional current/voltage transformer;

(2) The main insulation is SF6 gas medium, the insulation performance is stable and recoverable, and the insulation margin is large, which greatly improves the safety and reliability of the power grid;

(3) The remote module is placed in the shielded box on the tank body, the output signal of the current/voltage sensor is led to the remote module through the metal sealed terminal board with glass sintered aviation plug, and the influence of electromagnetic interference and VFTO is effectively suppressed;

(4) Use LPCT sensing to measure the current signal, and use the technology of air-core coil and hardware integration to realize the detection of the current signal for protection. The current transformer has high precision (meeting the requirements of 0.2S level) and good temperature stability (can be It works normally in the temperature range of -40℃～+75℃) and has very good transient characteristics (transient error is less than 2%);

(5) The technology of combining resistance-capacitance differential voltage sensor and software and hardware integration is used to realize the measurement of a high voltage. The voltage measurement accuracy is high (meeting the requirements of 0.2 level), and the temperature stability is good (can be controlled at -40℃～+75℃ temperature range), and has very good transient characteristics;

(6) Dual redundant configuration of current/voltage sensors, and dual sampling and comparison technology is used for the analog signal output by each sensor, which avoids the problem of protection malfunction caused by abnormal sampling, and has high reliability.

Description of drawings

The utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a combined sectional view of the utility model;

Fig. 2 is a side view of the utility model.

Detailed ways

The structure and working principle of the present utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the utility model provides an electronic current-voltage combined transformer, which includes a tank body 1, two air-core coils 2, two LPCT (low power current transformers) 3, and two capacitive voltage dividers Ring 4, sealed terminal board 5, remote module 6, box body 7, two adapter flanges 8, one primary conductor 9 and two pot insulators 10, which will be introduced respectively below.

The inside of the tank body 1 has an air chamber 11, and the top has an opening 12 communicating with the air chamber 11 and the outside, and a rectangular groove 13 is provided on the left and right sides.

Two air-core coils 2 are respectively fixed in two rectangular slots 13 of the tank body 1. The air-core coils 2 are used to sense the current signal for protection, and the output signal of the air-core coil 2 is the differential of the measured current. , the differential signal output by the air-core coil 2 is integrated and transformed by hardware integration technology, so that the protection current signal of LPCT 3 has a larger dynamic range and better transient characteristics, which meets the needs of relay protection.

Two LPCTs 3 are respectively fixed in two rectangular grooves 13 of the tank body 1, and the LPCTs 3 are used for sensing the current signal for measurement, so that the measurement current signal can have higher measurement accuracy and meet the requirements of electric energy metering. demand.

The two capacitive voltage divider rings 4 are respectively fixed inside the tank body 1 by an insulating medium, and in this embodiment, the two capacitor voltage divider rings 4 are respectively arranged at the upper and lower ends of the tank body 1 .

A box body 7 is fixed at the top opening 12 of the tank body 1. As shown in FIG.

The sealed terminal board 5 is made of metal and has a glass sintered aviation plug. The sealed terminal board 5 is fixed on the passage in the box body 7 and corresponds to the position of the opening 12 of the tank body 1. On the one hand, the air-core coil 2, The output signal of LPCT 3 and capacitive voltage divider ring 4 leads to the outside of gas chamber 11, on the other hand, it is used to seal the gas in gas chamber 11; because transient overvoltage (VFTO) will be generated when GIS circuit breaker or isolating switch operates, Therefore, the use of the sealed terminal board 5 can effectively prevent the VFTO from interfering with the remote module 6 .

由电阻两端获取的信号是被测一次电压的微分

利用远端模块6对其进行积分变换便可获知一次电压的信息。Both sides of the tank body 1 are respectively provided with a transfer flange 8, and the ends of the two transfer flanges 8 are also respectively fixed with a pot insulator 10, and the two ends of the cylindrical primary conductor 9 are connected with the two ends respectively. A basin-type insulator 10 is fixed, and the primary conductor 9 is located between the two capacitor voltage divider rings 4, so that the two capacitor voltage divider rings 4 are all located between the primary conductor 9 and the tank body 1, and the capacitor voltage divider ring 4 is connected to the tank body 1. The primary conductor 9 constitutes a high voltage capacitor C1, the medium of the high voltage capacitor is SF6 gas, and the capacitor voltage divider ring 4 and the tank body 1 constitute a low voltage capacitor C2, the capacitance of the low voltage capacitor is easily affected by the distributed capacitance of the output signal line; in order to improve Stability and transient performance of voltage measurement, at the two ends of the aforementioned low-voltage capacitor, a temperature coefficient of 5ppm is connected in parallel with a small resistance precision resistor R (this resistor is located in the remote module 6), and the resistance value of the resistor is far away. Less than the capacitive reactance of the low voltage capacitor

The signal obtained from both ends of the resistor is the differential of the measured primary voltage

The information of the primary voltage can be obtained by performing integral transformation with the remote module 6 .

The remote module 6 is also arranged in the box body 7 and fixed on the outside of the sealed terminal board 5 .

When working, the air-core coil 2 and LPCT 3 are used to sense the measured primary current information, among which, the air-core coil 2 senses the current signal for protection, and the LPCT 3 senses the current signal for measurement; and each capacitive voltage divider ring 4 A coaxial capacitor voltage divider is formed with the tank body 1 and the primary conductor 9 on both sides, and the two capacitor voltage divider rings 4 are respectively the middle electrodes of the two coaxial capacitor voltage dividers, and the coaxial capacitor voltage divider is used for In order to sense the measured primary voltage information, the remote module 6 collects and processes the output signals of the air core coil 2, LPCT 3 and the coaxial capacitor voltage divider on the spot. For each analog input signal, the remote module is designed with two independent The sampling circuit completes dual sampling, compares and verifies the sampling values of two channels in real time, realizes the hardware self-test function of the sampling circuit, and avoids protection malfunction caused by abnormal sampling; while the output signal of the remote module 6 is a digital signal, the output signal uses fiber optic transmission.

It should be noted that the utility model is equipped with two sets of air-core coil 2, LPCT 3, coaxial capacitor voltage divider and remote module 6, and the two sets of measuring elements are used as backups for each other, and the failure of one set of measuring elements will not affect The normal operation of another set of measuring components, thus having higher reliability.

The above embodiments are only to illustrate the technical ideas of the utility model, and cannot limit the protection scope of the utility model with this. Any changes made on the basis of the technical solutions according to the technical ideas proposed by the utility model all fall into the scope of the utility model. within the scope of the new protection.

Claims (2)

1. an electronic current voltage combination transformer is characterized in that: comprise a tank body (1), two hollow coils (2), two LPCT (3), two capacitance partial pressure rings (4), a sealed end daughter board (5), two remote end modules (6), a casing (7), two switchings flange (8), a Primary Conductor (9) and two disc insulators (10); Wherein, tank body (1) has an opening (12), is used for sensing and protects the both sides that are individually fixed in tank body (1) with the hollow coil (2) of current signal, is used for sensing measurement also is individually fixed in tank body (1) with the LPCT (3) of current signal both sides; Two capacitance partial pressure rings (4) are located at the inboard two ends up and down of tank body (1) respectively; Casing (7) is fixed in tank body (1) top, and the opening of corresponding tank body (1) forms the passage of up/down perforation, and sealed end daughter board (5) is located at the channel position in the casing (7), and the opening (12) of tank body (1) blocked, remote end module (6) also is located in the casing (7), and is positioned at the outside of sealed end daughter board (5); Two switching flanges (8) are located at the both sides of tank body (1) respectively, and the end of the flange (8) of respectively transferring is also fixed a disc insulator (10) respectively, the two ends of Primary Conductor (9) are fixing with two disc insulators (10) respectively, and described Primary Conductor (9) is positioned between two capacitance partial pressure rings (4).

2. a kind of electronic current voltage combination transformer as claimed in claim 1, it is characterized in that: the left and right sides of described tank body (1) forms rectangular channel (13) respectively, and hollow coil (2) and LPCT (3) all are fixed in this rectangular channel (13).

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