阅读说明：本技术 一种电流采样切换电路 (Current sampling switching circuit ) 是由 曹宏 马丽娜 张紫阳 王伟名 陈科威 杨相玉 于 2019-11-08 设计创作，主要内容包括：本发明涉及一种电流采样切换电路,属于电力系统无功补偿装置的电流采集领域,包括四个采样回路,分别为I段进线第一采样支路、I段进线第二采样支路、II段进线第一采样支路和II段进线第二采样支路；本发明通过设置I段柜间联锁开关和II段柜间联锁开关,实现了通过电气联锁的方式完成采样切换的过程,以保证I段采样控制器和II段采样控制器采集信号的正确性。本发明的电流采样切换电路设计简单,实用性高,可降低对控制器进行电流采样与开关位置判断与切换的要求,提高产品标准化水平。(The invention relates to a current sampling switching circuit, which belongs to the field of current acquisition of reactive power compensation devices of an electric power system and comprises four sampling loops, namely an I-section incoming line first sampling branch, an I-section incoming line second sampling branch, a II-section incoming line first sampling branch and an II-section incoming line second sampling branch; according to the invention, the process of completing sampling switching in an electrical interlocking manner is realized by arranging the inter-cabinet interlock switch of the section I and the inter-cabinet interlock switch of the section II, so that the correctness of signals acquired by the sampling controller of the section I and the sampling controller of the section II is ensured. The current sampling switching circuit is simple in design and high in practicability, can reduce the requirements for current sampling and switch position judgment and switching of the controller, and improves the product standardization level.)

1. The utility model provides a current sampling switching circuit, its characterized in that, includes the first sampling branch road of I section inlet wire, I section inlet wire second sampling branch road, the first sampling branch road of II section inlet wire and II section inlet wire second sampling branch road, wherein:

the I-section incoming line first sampling branch comprises a first I-section current transformer (101), the primary side of the first I-section current transformer (101) is used for connecting one phase incoming line of an I-section system, and the secondary side of the first I-section current transformer (101) is connected with an I-section sampling controller (105);

the I section incoming line second sampling branch comprises a second I section current transformer (111), the primary side of the second I section current transformer (111) is used for connecting the other phase incoming line of the I section system, the secondary side of the second I section current transformer (111) is connected to a II section sampling controller (115) through an inter-II section cabinet interlocking switch (114), and the inter-II section cabinet interlocking switch (114) comprises a normally open contact (QF1) of a bus coupler cabinet switch and a normally closed contact (QF3) of an inter-II section main transformer incoming line cabinet switch;

the second-section incoming line first sampling branch comprises a first second-section current transformer (112), the primary side of the first second-section current transformer (112) is used for connecting one phase incoming line of a second-section system, and the secondary side of the first second-section current transformer (112) is connected with a second-section sampling controller (115);

the second sampling branch of the II section incoming line comprises a second II section current transformer (102), the primary side of the second II section current transformer (102) is used for connecting the other phase incoming line of the II section system, the secondary side of the second II section current transformer (102) is connected with the I section sampling controller (105) through an I section inter-cabinet interlocking switch (104), and the I section inter-cabinet interlocking switch (104) comprises a normally open contact (QF1) of a bus coupler cabinet switch and a normally closed contact (QF2) of an I section main transformer incoming line cabinet switch.

2. The current sampling switching circuit according to claim 1, wherein the secondary side of the second I-section current transformer (111) is connected in parallel with an I-section voltage limiting protection device (113) for limiting the voltage when the secondary side of the second I-section current transformer (111) is short-circuited.

3. The current sampling switching circuit according to claim 1 or 2, wherein the secondary side of the second segment II current transformer (102) is connected in parallel with a segment II voltage limiting protection device (103) for limiting the voltage when the secondary side of the second segment II current transformer (102) is short-circuited.

Technical Field

The invention belongs to the field of current collection of reactive power compensation devices of power systems, and particularly relates to a current sampling switching circuit.

Background

The reactive compensation device is widely applied to industrial systems, electric power systems, traffic systems, computer systems, new energy systems and daily life, and the reactive compensation device is in an indispensable and very important position in the power supply systems of the systems, so that the loss of a power grid can be reduced to the maximum extent by reasonably selecting the reactive compensation device, and the quality of the power grid is improved; conversely, if the reactive power compensation device is selected or used improperly, voltage fluctuation, harmonic increase and other problems of the power supply system may be caused.

At present, the core controller (i.e. sampling controller) of most reactive power compensation devices only has one group of current acquisition input ports, all are in single-section compensation mode, and only current acquisition and compensation control can be performed for a certain section of incoming line system, when facing a system scheme of two power incoming lines and multiple power incoming lines (a section of system bus and a section of system bus in the section I are respectively connected with at least one power supply), the core controller under the section of system divided by an incoming line cabinet does not send compensation information, and the reactive power compensation devices do not operate, thereby causing resource waste of the devices. For example, when the I section of incoming line cabinet is closed, the bus coupler cabinet is closed, and the II section of incoming line cabinet is divided, the current transformer of the II section system cannot acquire a current signal, the II section sampling controller does not send out compensation information, and the reactive power compensation device of the II section system does not operate, so that resource waste is caused.

Disclosure of Invention

The invention aims to provide a current sampling switching circuit which is used for solving the problem that a controller of a reactive power compensation device of a section of system cannot acquire current signals when power supply inlet wires of a section I system and a section II system exist simultaneously in the prior art.

Based on the above purpose, a technical scheme of the current sampling switching circuit is as follows:

the method comprises the following steps: first sampling branch circuit of I section inlet wire, the second sampling branch circuit of I section inlet wire, the first sampling branch circuit of II section inlet wire and the second sampling branch circuit of II section inlet wire, wherein:

the I-section incoming line first sampling branch comprises a first I-section current transformer (101), the primary side of the first I-section current transformer (101) is used for connecting one phase incoming line of an I-section system, and the secondary side of the first I-section current transformer (101) is connected with an I-section sampling controller (105);

the I section incoming line second sampling branch comprises a second I section current transformer (111), the primary side of the second I section current transformer (111) is used for connecting the other phase incoming line of the I section system, the secondary side of the second I section current transformer (111) is connected to a II section sampling controller (115) through an inter-II section cabinet interlocking switch (114), and the inter-II section cabinet interlocking switch (114) comprises a normally open contact (QF1) of a bus coupler cabinet switch and a normally closed contact (QF3) of an inter-II section main transformer incoming line cabinet switch;

the second-section incoming line first sampling branch comprises a first second-section current transformer (112), the primary side of the first second-section current transformer (112) is used for connecting one phase incoming line of a second-section system, and the secondary side of the first second-section current transformer (112) is connected with a second-section sampling controller (115);

the second sampling branch of the II section incoming line comprises a second II section current transformer (102), the primary side of the second II section current transformer (102) is used for connecting the other phase incoming line of the II section system, the secondary side of the second II section current transformer (102) is connected with the I section sampling controller (105) through an I section inter-cabinet interlocking switch (104), and the I section inter-cabinet interlocking switch (104) comprises a normally open contact (QF1) of a bus coupler cabinet switch and a normally closed contact (QF2) of an I section main transformer incoming line cabinet switch.

The beneficial effects of the above technical scheme are:

the current sampling switching circuit of the invention is divided into the following five working states:

the first working state is that when an incoming cabinet of a section I system is closed, a bus coupler cabinet is disconnected and an incoming cabinet of a section II system is disconnected, an I section sampling controller (105) collects output signals of a first section I current transformer (101), and a section II sampling controller (115) does not collect signals;

the second working state is that when the incoming line cabinet of the I-section system is closed, the bus coupler cabinet is closed and the incoming line cabinet of the II-section system is disconnected, the I-section sampling controller (105) collects the output signal of the first I-section current transformer (101), and the II-section sampling controller (115) collects the output signal of the second I-section current transformer (111);

the third working state is that when the incoming line cabinet of the I-section system is disconnected, the bus coupler cabinet is disconnected and the incoming line cabinet of the II-section system is closed, the II-section sampling controller (115) collects output signals of the first II-section current transformer (112), and the I-section sampling controller (105) does not collect signals;

when the incoming line cabinet of the I-section system is disconnected, the bus coupler cabinet is closed and the incoming line cabinet of the II-section system is closed, the I-section sampling controller (105) collects output signals of the second II-section current transformer (102), and the II-section sampling controller (115) collects output signals of the first II-section current transformer (112);

and in the fifth working state, when the incoming line cabinet of the I-section system is closed, the bus coupler cabinet is disconnected and the incoming line cabinet of the II-section system is closed, the I-section sampling controller (105) collects output signals of the first I-section current transformer (101), and the II-section sampling controller (115) collects output signals of the first II-section current transformer (112).

According to the invention, when power supply inlet wires of the I-section system and the II-section system exist simultaneously, the process of completing sampling switching in an electrical interlocking mode is realized by arranging the I-section inter-cabinet interlocking switch (104) and the II-section inter-cabinet interlocking switch (114), so that the correctness of signals acquired by the I-section sampling controller and the II-section sampling controller is ensured. The current sampling switching circuit is simple in design and high in practicability, can reduce the requirements for current sampling and switch position judgment and switching of a controller of the reactive compensation device, and improves the product standardization level.

Furthermore, the secondary side of the second I-section current transformer (111) is connected in parallel with an I-section voltage limiting protection device (113) for limiting the voltage of the short circuit of the secondary side of the second I-section current transformer (111) when the interlocking switch (114) between the I-section cabinets is in an open circuit, so that the problems of high voltage breakdown discharge, even fire and the like caused by high voltage generated by the open circuit of the secondary side of the second I-section current transformer are avoided.

Furthermore, the secondary side of the second II-section current transformer (102) is connected in parallel with a II-section voltage limiting protection device (103) for limiting the voltage of the secondary side of the second II-section current transformer (102) during short circuit when the interlocking switch (104) between the I-section cabinets is in open circuit, and the problems of high voltage breakdown discharge, even fire hazard and the like caused by high voltage generated by the open circuit of the secondary side of the second II-section current transformer are avoided.

Drawings

FIG. 1 is a current sampling switching circuit diagram of the present invention;

FIG. 2 is a primary circuit diagram corresponding to the current sampling switching circuit of the present invention;

the reference numerals of fig. 1 are explained as follows:

101, a first I-section current transformer; 111, a second I-section current transformer; 102, a second segment II current transformer; 112, a first segment II current transformer; 105, a segment I sampling controller; 115, a II-section sampling controller; 104, an inter-I-section cabinet interlocking switch; 114, inter-II-section cabinet interlocking switch; QF1, a normally open contact of a bus coupler cabinet switch; QF2, normally closed contact of I section main transformer incoming line cabinet switch; QF3, normally closed contact of the incoming line cabinet switch of the II-section main transformer; 103, a section II voltage limiting protection device; and 113, a section I voltage limiting protection device.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings.

The invention provides a current sampling switching circuit, comprising: the first sampling branch circuit of I section inlet wire, I section inlet wire second sampling branch circuit, II section inlet wire first sampling branch circuit and II section inlet wire second sampling branch circuit. As shown in fig. 1, the first sampling branch of the I-section incoming line includes a first I-section current transformer 101, a primary side of the first I-section current transformer 101 is connected to one of the phase incoming lines of the I-section system, and a secondary side of the first I-section current transformer 101 is connected to a sampling interface of an I-section sampling controller 105 (in this embodiment, a voltage sampling controller).

The second sampling branch of the I-section incoming line comprises a second I-section current transformer 111, the primary side of the second I-section current transformer 111 is connected with the other phase incoming line of the I-section system, the secondary side of the second I-section current transformer 111 is connected with the sampling interface of the II-section sampling controller 115 (the voltage sampling controller in this embodiment) through an inter-II-section cabinet interlock switch 114, and the inter-II-section cabinet interlock switch 114 comprises a normally open contact QF1 of a bus-coupled cabinet switch and a normally closed contact QF3 of an inter-II-section main transformer incoming line cabinet switch. In fig. 1, the secondary side of the second I-section current transformer 111 is connected in parallel with an I-section voltage limiting protection device 113 for limiting the voltage when the secondary side of the second I-section current transformer 111 is short-circuited.

The second-section incoming line first sampling branch comprises a second-section current transformer 112, a primary side of the second-section current transformer 112 is connected with one of the phase incoming lines of the second-section system, and a secondary side of the second-section current transformer 112 is connected with a sampling interface of a second-section sampling controller 115.

The second sampling branch of the second section incoming line comprises a second section II current transformer 102, the primary side of the second section II current transformer 102 is connected with the other phase incoming line of the second section II system, the secondary side of the second section II current transformer 102 is connected with the sampling interface of the section I sampling controller 105 through an inter-cabinet interlock switch 104 of the section I, and the inter-cabinet interlock switch 104 of the section I comprises a normally open contact QF1 of a bus-coupled cabinet switch and a normally closed contact QF2 of an incoming line cabinet switch of the section I main transformer. In fig. 1, a secondary side of the second II-stage current transformer 102 is connected in parallel with a II-stage voltage limiting protection device 103 for limiting a voltage when the secondary side of the second II-stage current transformer 102 is short-circuited.

The primary circuit corresponding to the current sampling switching circuit in fig. 1 is shown in fig. 2, the left-side bus in the figure is an I-section bus, the right-side bus is an II-section bus, the I-section main transformer incoming cabinet is an I-section main transformer incoming cabinet, the II-section main transformer incoming cabinet is an II-section main transformer incoming cabinet, and the interconnection cabinet is a buscouple cabinet.

The current sampling switching circuit shown in fig. 1 operates as follows:

1) the I-section inlet line cabinet is closed (namely the I-section main transformer inlet line cabinet is closed), the busbar cabinet is divided, the II-section inlet line cabinet is divided (namely the II-section main transformer inlet line cabinet is disconnected), the I-section inter-cabinet interlock 104 is opened and the II-section inter-cabinet interlock 114 is opened through the interlock loop, and the I-section sampling controller 105 acquires the A-phase current 101 current signal of the I-section system inlet line; the II-section sampling controller 115 has no current signal input and stops operation, the secondary side of the C-phase current 111 of the inlet wire of the I-section system is short-circuited, the voltage is increased, the I-section voltage limiting protection device 113 acts (the I-section voltage limiting protection device is not called), the voltage is limited in a proper range, and the voltage limiting protection module automatically restores to a standby state when the secondary output voltage of the current transformer disappears.

2) The I-section incoming line cabinet closing, the bus coupler cabinet closing and the II-section incoming line cabinet dividing are carried out, through the interlocking 104 circuit breaking between the I-section cabinets and the interlocking 114 passage between the II-section cabinets of the interlocking loop, and the I-section sampling controller 105 collects the A-section incoming line phase current 101 current signals of the I-section system; the second-stage sampling controller 115 collects the current signals of the phase-C current 111 of the incoming line of the first-stage system.

3) The I-section incoming line cabinet is divided (namely, the incoming line cabinet of the I-section system is disconnected), the bus coupler cabinet is divided, the II-section incoming line cabinet is closed (namely, the incoming line cabinet of the II-section system is closed), the I-section inter-cabinet interlock 104 is disconnected and the II-section inter-cabinet interlock 114 is disconnected through the interlock loop, the I-section sampling controller 105 has no current signal input and stops operation, the secondary side of the A-section incoming line phase current 102 of the II-section system is short-circuited, the voltage is increased, the II-section voltage limiting protection device 103 acts to limit the voltage within a proper range, and when the secondary output voltage of the current transformer disappears, the voltage limiting protection module automatically restores to a standby; the second-stage sampling controller 115 collects the second-stage system incoming line C-phase current 112 current signals.

4) The I-section incoming line cabinet is divided into a bus coupler cabinet and a II-section incoming line cabinet, the I-section incoming line cabinet is connected with the bus coupler cabinet, the II-section incoming line cabinet is connected with the bus coupler cabinet, the I-section inter-cabinet interlock 104 is connected with the II-section inter-cabinet interlock 114 in the interlock loop, and the I-section sampling controller 105 acquires phase current 102 current signals of the incoming line A of the II-section system; the second-stage sampling controller 115 collects the second-stage system incoming line C-phase current 112 current signals.

5) The I section of incoming line cabinet is closed, the bus coupler cabinet is divided, the II section of incoming line cabinet is closed, the I section of inter-cabinet interlock 104 of the interlock loop is opened, the II section of inter-cabinet interlock 114 is opened, the I section of sampling controller 105 collects the A phase current 101 current signal of the incoming line of the I section of system, meanwhile, the secondary side of the A phase current 102 of the incoming line of the II section of system is short-circuited, the voltage is increased, the II section of voltage limiting protection device 103 acts to limit the voltage in a proper range, and when the secondary output voltage of the current transformer disappears, the voltage limiting protection module automatically restores to a standby state; the II-section sampling controller 115 collects current signals of the II-section system inlet wire C-phase current 112, meanwhile, the I-section system inlet wire C-phase current 111 is short-circuited at the secondary side, the voltage is increased, the I-section voltage limiting protection device 113 acts to limit the voltage within a proper range, and the voltage limiting protection module automatically restores to a standby state when the secondary output voltage of the current transformer disappears.

In summary, the current sampling branches are switched on or off by judging the switch on-off states of the I-section incoming line cabinet, the bus coupler cabinet and the II-section incoming line cabinet according to the switch on-off states of the I-section incoming line cabinet, the bus coupler cabinet and the II-section incoming line cabinet. In addition, in this embodiment, the switch on/off states of the first-stage incoming cabinet, the bus coupler cabinet and the second-stage incoming cabinet can indicate the power supply mode of the system, that is, when the first-stage incoming cabinet is closed, the bus coupler cabinet is separated and the second-stage incoming cabinet is closed, the first-stage system and the second-stage system independently supply power to both sides; when the bus coupler cabinets are closed, one section of incoming line cabinet is divided into two sections, and the other section of incoming line cabinet is closed, the power supply connected with the system on the side where the incoming line cabinets are closed supplies power to the two sections of systems; when the bus coupler cabinet is divided, one section of incoming line cabinet is divided, and the other section of incoming line cabinet is combined, the power supply connected with the side system where the incoming line cabinets are combined independently supplies power to the section of system (namely the states of the I section of incoming line cabinet, the bus coupler cabinet and the II section of incoming line cabinet) so as to provide correct current signals for the corresponding controller, and the corresponding controller can realize correct acquisition of the current signals.

When the power inlet wires of the I-section system and the II-section system exist at the same time, the current sampling switching circuit can enable the I-section sampling controller and the II-section sampling controller to normally acquire current signals, so that the I-section reactive compensation device performs reactive compensation according to the current signals acquired by the I-section sampling controller, and similarly, the II-section reactive compensation device performs reactive compensation according to the current signals acquired by the II-section sampling controller, thereby realizing the maximum utilization of the reactive compensation device and avoiding the resource waste; simultaneously, two reactive power compensator put into together, and the input can increase the reactive power compensation effect to the system, helps the fast and stable of I section system and II section system.

In addition, when the inter-cabinet interlock 104 of the I section and the inter-cabinet interlock 114 of the II section are in open circuit, the inter-cabinet interlock 103 of the II section and the inter-cabinet interlock 114 of the I section can play a role in voltage limiting protection for high voltage generated by open circuit of a secondary coil of a current transformer in a loop, and the problems of high voltage breakdown discharge, even fire and the like caused by high voltage generated by open circuit of a secondary side of the current transformer are avoided.

In this embodiment, the I-stage sampling controller 105 and the II-stage sampling controller 115 are both reactive compensation controllers, and collect both current signals and voltage signals, but the voltage signals do not need to be switched.

The current sampling switching circuit is matched with a sampling controller of a reactive compensation device for use, can realize the power supply mode of a dual-power supply system or a multi-power supply system, has strong flexibility, can realize the automatic switching of current sampling, does not need the controller to judge and switch the current sampling and the switch position, and improves the product standardization level.