阅读说明：本技术 一种可自动调节的多变比电流互感器 (But automatically regulated's multiple transformation ratio current transformer ) 是由 杨君祥 侯祥玉 朱崇健 于 2020-11-12 设计创作，主要内容包括：本发明公开一种可自动调节的多变比电流互感器,包括电流监测器,及一次侧共用的多变比输出线圈和控制电流线圈；多变比输出线圈的定端子连接到一个互感器二次接线端子,其余各变比输出的动端子分别连接到电流监测器中的继电器常闭端子和常开端子；常闭端子和常开端子的共用闸刀端连接到另一互感器二次接线端子；控制电流线圈的输出端连接到电流监测器的电流采样端,根据采集到的控制电流线圈的电流大小控制共用闸刀端接通常闭端子或常开端子,从而调节多变比输出线圈的输出变比。本发明可实现自动切换或手动按钮切换,不用停电重新接线,无需占用额外空间,可靠性、安全性大幅提高。(The invention discloses an automatically adjustable multi-transformation ratio current transformer, which comprises a current monitor, a multi-transformation ratio output coil and a control current coil, wherein the multi-transformation ratio output coil and the control current coil are shared on a primary side; the fixed terminal of the multi-transformation ratio output coil is connected to a secondary wiring terminal of a mutual inductor, and the movable terminals of the rest of the multi-transformation ratio outputs are respectively connected to a normally closed terminal and a normally open terminal of a relay in the current monitor; the common knife switch end of the normally closed terminal and the normally open terminal is connected to the secondary connecting terminal of the other mutual inductor; the output end of the control current coil is connected to the current sampling end of the current monitor, and the common knife switch end is controlled to be connected with the normally closed terminal or the normally open terminal according to the collected current of the control current coil, so that the output transformation ratio of the multi-transformation-ratio output coil is adjusted. The invention can realize automatic switching or manual button switching, does not need to be powered off and rewired, does not need to occupy extra space, and greatly improves the reliability and the safety.)

1. A multi-transformation ratio current transformer capable of automatically adjusting is characterized by comprising a current monitor, a multi-transformation ratio output coil and a control current coil shared by a primary side; the fixed terminal (s 3) of the multi-transformation ratio output coil is connected to a secondary connecting terminal (s 1) of a mutual inductor, and the movable terminals (s 4, s 5) of the other transformation ratio outputs are respectively connected to a normally closed terminal (12) and a normally open terminal (14) of a relay in the current monitor; the common knife switch end (11) of the normally closed terminal (12) and the normally open terminal (14) is connected to the secondary connecting terminal (s 2) of the other mutual inductor; the output end of the control current coil is connected to the current sampling end of the current monitor, and the common knife switch end (11) is controlled to be connected with the normally closed terminal (12) or the normally open terminal (14) according to the collected current of the control current coil, so that the output transformation ratio of the multi-transformation-ratio output coil is adjusted.

2. The automatically adjustable multi-ratio current transformer of claim 1, further comprising a manual change-over ratio switch and a manual/automatic change-over switch; the manual ratio-switching ratio switch comprises ratio gears (h 1, h 2), and the ratio gears (h 1, h 2) are respectively connected to ratio output terminals (s 4, s 5) of the multi-ratio output coil; the manual/automatic change-over switch comprises a manual gear (1-2) and an automatic gear (3-4), one end of the manual gear (1-2) is connected to the manual change-over ratio switch, and the other end of the manual gear (1-2) is connected with a secondary wiring terminal (s 2) of the mutual inductor; one end of the automatic gear (3-4) is connected to the common knife switch end (11) of the current monitor, and the other end of the automatic gear is also connected with a secondary connecting terminal (s 2) of the mutual inductor.

3. The automatically adjustable multi-ratio current transformer according to claim 2, characterized in that the output of the control current coil is further provided with a short-circuit switch (5-6).

Technical Field

The invention relates to the technical field of power parameter adjustment and control, in particular to an automatically adjustable multi-transformation ratio current transformer.

Background

The multi-transformation ratio current transformer is derived mainly aiming at the requirement of a metering special CT on transformation ratio, and is different from the traditional CT in that a secondary winding is tapped at the middle part, and the principle is that the turn ratio of a first winding to a second winding is in inverse proportion to current. Therefore, the transformation ratio of the connection with the middle tap is small, and the transformation ratio of the connection with the two ends of the secondary winding is large.

The current multi-transformation ratio current transformer needs to be manually replaced after power failure in the process of replacing transformation ratio, so that time and labor are wasted, and the potential hazard of loss caused by wrong wiring can exist. The existing automatic adjusting device and method for the multi-transformation ratio current transformer have the following problems:

1) an extra current transformer and an extra control box are needed, so that the occupied space is large, and the method cannot be well suitable for the existing installation space;

2) the transformation ratio can not be switched manually, if components break down, serious problems such as open circuit and overload of the mutual inductor can be caused, and the mutual inductor is burnt down or a circuit is tripped and powered off due to long-time operation.

3) The external connection is too much, and the anti-theft performance is poor.

The structure of the existing multi-transformation ratio current transformer is shown in figure 1, and the schematic diagram is shown in figure 2. The transformation ratio can be made into double transformation ratios such as 100-200/5, if the user needs 100/5, then the S1 and S2 terminals are used; if the user desires 200/5, then the S1 and S3 terminals are used; when a user uses 100/5 to change to 200/5, the wiring needs to be manually changed after power failure, which not only wastes time and labor, but also can cause wiring errors and huge loss.

Disclosure of Invention

Aiming at the problems, the invention aims to provide the multi-transformation ratio current transformer which can realize automatic switching or manual button switching, does not need to be powered off for rewiring, does not need to occupy extra space, and greatly improves the reliability and the safety aiming at the problems of difficult transformation ratio switching, easy error making, easy failure, easy tampering, large occupied space and the like of the conventional multi-transformation ratio current transformer. The technical scheme is as follows:

a multi-transformation ratio current transformer capable of automatically adjusting comprises a current monitor, a multi-transformation ratio output coil and a control current coil shared by a primary side; the fixed terminal of the multi-transformation ratio output coil is connected to a secondary wiring terminal of a mutual inductor, and the movable terminals of the rest of the multi-transformation ratio outputs are respectively connected to a normally closed terminal and a normally open terminal of a relay in the current monitor; the common knife switch end of the normally closed terminal and the normally open terminal is connected to the secondary connecting terminal of the other mutual inductor; the output end of the control current coil is connected to the current sampling end of the current monitor, and the common knife switch end is controlled to be connected with the normally closed terminal or the normally open terminal according to the collected current of the control current coil, so that the output transformation ratio of the multi-transformation-ratio output coil is adjusted.

Further, the device also comprises a manual ratio switching switch and a manual/automatic switching switch; the manual ratio switching switch comprises each ratio gear which is respectively connected to each ratio output terminal of the multi-ratio output coil; the manual/automatic change-over switch comprises a manual gear and an automatic gear, one end of the manual gear is connected to the manual change-over ratio-changing switch, and the other end of the manual gear is connected with a secondary wiring terminal of the mutual inductor; one end of the automatic gear is connected to the common knife switch end of the current monitor, and the other end of the automatic gear is also connected with a secondary wiring terminal of the mutual inductor.

Furthermore, the output end of the control current coil is also provided with a short-circuit switch.

The invention has the beneficial effects that: the intelligent switching part adopts the current monitoring relay to automatically switch, and meanwhile, a manual switch is added, so that automatic switching or manual button switching can be realized, the power failure is not needed, the rewiring is not needed, the extra space is not needed, and the reliability and the safety are greatly improved.

Drawings

Fig. 1 is a schematic structural diagram of a conventional multi-ratio current transformer.

Fig. 2 is a schematic diagram of a conventional multi-ratio current transformer.

Fig. 3 is a schematic structural diagram of the automatically adjustable multi-ratio current transformer of the present invention.

Fig. 4 is a schematic diagram of an automatically adjustable multiple ratio current transformer of the present invention.

Detailed Description

The invention is described in further detail below with reference to the figures and specific embodiments. As shown in fig. 3 and 4, the self-adjustable multi-ratio current transformer of the present invention includes a current monitor, and a multi-ratio output coil and a control current coil shared by a primary side; the fixed terminal s3 of the multi-transformation ratio output coil is connected to a secondary connecting terminal s1 of a mutual inductor, and the movable terminals s4 and s5 of the rest of the multi-transformation ratio outputs are respectively connected to a normally closed terminal 12 and a normally open terminal 14 of a relay in the current monitor; the common knife switch end 11 of the normally closed terminal 12 and the normally open terminal 14 is connected to the secondary connecting terminal s2 of the other mutual inductor; the output end of the control current coil is connected to the current sampling end of the current monitor, and the common knife switch end 11 is controlled to be connected with the normally closed terminal 12 or the normally open terminal 14 according to the collected current of the control current coil, so that the output transformation ratio of the multi-transformation-ratio output coil is adjusted.

The embodiment also comprises a manual ratio switching switch and a manual/automatic switching switch; the manual ratio-switching switch comprises ratio gears h1 and h2, wherein the ratio gears h1 and h2 are respectively connected to ratio output terminals s4 and s5 of a multi-ratio output coil; the manual/automatic change-over switch comprises a manual gear 1-2 and an automatic gear 3-4, one end of the manual gear 1-2 is connected to the manual change-over ratio switch, and the other end of the manual gear 1-2 is connected with a secondary wiring terminal s2 of the mutual inductor; one end of the automatic gear 3-4 is connected to the common knife switch end 11 of the current monitor, and the other end of the automatic gear is also connected to a secondary connection terminal s2 of the transformer. The output end of the control current coil is also provided with a short-circuit switch 5-6.

The transformation ratios output by the terminals S1 and S2 in FIG. 4 are the transformation ratios which can be automatically switched according to the current magnitude; besides automatic switching, manual switching of the transformation ratio can be realized by pulling a switch. No rewiring and power outages are required.

When the manual/automatic change-over switch is switched to the automatic gear, the line at the side of 1-2 of the manual gear is disconnected, the line at the side of 3-4 of the automatic gear is connected, the control winding short-circuit switch 5-6 is disconnected, and the current monitor power switch 7-8 is connected.

When the manual/automatic change-over switch is switched to a manual gear, a line on the side of the manual gear is switched on by 1-2, a line on the side of the automatic gear is switched off by 3-4, a control winding current short-circuit wire is switched on by 5-6, and a current monitor power switch 7-8 is switched off.

The automatic switching implementation principle is as follows:

the current transformer outputs a group of control current signals, and the control winding and the output winding are shared for the first time, so that the control winding can embody the current of the primary current and the current of the output current winding.

1) When the electricity is normally used, the common knife edge 11 and the normally closed terminal 12 of the current monitor are connected, and the output of the S1 and S2 terminals is small transformation ratio;

2) when the current monitor monitors that the current output by the control winding is larger than a set current threshold, the current monitor acts, the common knife switch end 11 and the normally closed terminal 12 are disconnected, the common knife switch end 11 and the normally open terminal 14 are connected, and the output of the S1 and the S2 terminals is a large transformation ratio;

3) when the control winding current is reduced to a set reset value, the monitor is operated, the common knife end 11 and the normally open terminal 14 are disconnected, the common knife end 11 and the normally closed terminal 12 are connected, and the output of the terminals S1 and S2 is a small transformation ratio.

The principle of manual switching:

when the manual/automatic change-over switch is switched to a manual gear, the manual/automatic change-over switch is in a manual change-over mode, and at the moment, a circuit can be selected by changing a transformation ratio gear of the manual change-over transformation ratio switch, so that the transformation ratio output by the current transformer is changed.