Sampling current loop and electric energy quality management system

Abstract

The invention belongs to the technical field of electrical manufacturing, and aims to provide a sampling current loop and an electric energy quality management system. The sampling current loop comprises an intermediate relay and a main switch, one end of a normally closed contact of the intermediate relay is connected with a first terminal of a secondary winding of a current transformer, and the other end of the normally closed contact of the intermediate relay is connected with a second terminal of the secondary winding of the current transformer. One end of the normally-closed contact of the intermediate relay is further connected with a first wiring end of an electric energy control element in the electric energy management device, the other end of the normally-closed contact of the intermediate relay is further connected with a second wiring end of the electric energy control element, and a coil of the intermediate relay and the electric energy management device are both connected with a power supply through a main switch. The electric energy quality management system comprises the sampling current loop, a current transformer and an electric energy management device. According to the invention, automatic short circuit of the secondary side of the current transformer can be realized, and the safety is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical manufacturing, and particularly relates to a sampling current loop and a power quality management system. Background Art

[0002] Power quality control devices such as reactive power compensation devices, passive filter devices, and active filter devices can optimize the performance of the power system to ensure the quality and reliability of power supply. During operation, power quality control devices usually rely on a sampling current loop to obtain real-time current information from the power system to understand the actual operating conditions of the power system and adjust their own operating modes accordingly.

[0003] Among them, the sampling current loop is responsible for converting the current signal collected by a current transformer (CT) into a small current signal suitable for secondary equipment processing and finally transmitting it to the power quality control device for analysis. If the secondary side of the current transformer is open-circuited, it may cause a high voltage to be generated on the secondary side, which may further cause equipment damage or personal injury. To prevent the secondary side of the current transformer from being open-circuited during operation, it is usually necessary to short-circuit the secondary side of the current transformer before maintaining or testing the power quality control device. In the prior art, the secondary side of the current transformer is usually short-circuited by manually connecting a secondary wire or a special short-circuit bar to the secondary terminal (i.e., the interface connecting the current transformer and the power quality control device).

[0004] However, in the process of using the prior art, the inventor found that the prior art has at least the following problems:

[0005] Traditional short-circuiting methods rely on manually connecting wires or short-circuit bars, which require a high level of professionalism from operators, and there is a risk of misoperation in manual operations, such as missed short-circuiting, misaligned short-circuiting, and insecure short-circuiting. The risk of open-circuit operation of the current transformer cannot be effectively avoided. Summary of the Invention

[0006] The present invention aims to solve the above technical problems to at least a certain extent, and provides a sampling current loop and a power quality management system.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a sampled current loop, including an intermediate relay and a main switch. One end of the normally closed contact of the intermediate relay is connected to the first terminal of the secondary winding of the current transformer, and the other end of the normally closed contact of the intermediate relay is connected to the second terminal of the secondary winding of the current transformer. One end of the normally closed contact of the intermediate relay is also connected to the first terminal of the power control element in the power management device, and the other end of the normally closed contact of the intermediate relay is also connected to the second terminal of the power control element. The coil of the intermediate relay and the power management device are both connected to the power supply through the main switch.

[0009] In a possible design, the main switch adopts a load switch; correspondingly, the sampled current loop further includes a first fuse. The current input terminal of the main switch is connected to the power supply through the first fuse, and the current output terminal of the main switch is connected to the coil of the intermediate relay and the power management device.

[0010] In a possible design, the power management device adopts a reactive power compensation device or a passive filter device; correspondingly, the power control element adopts a capacitor controller.

[0011] In a possible design, the sampled current loop further includes a second fuse and a lightning arrester. One end of the second fuse is connected to the junction point of the coil of the intermediate relay and the main switch, and the other end of the second fuse is grounded through the lightning arrester.

[0012] In a possible design, the main switch adopts a circuit breaker.

[0013] In a possible design, the power management device adopts a static var generator or an active power filter; correspondingly, the power control element adopts an AMK.

[0014] In a possible design, the sampled current loop further includes a first static and dynamic plug-in, a second static and dynamic plug-in, and a third static and dynamic plug-in. The first static and dynamic plug-in is connected between the main switch and the power supply, the second static and dynamic plug-in is connected between the main switch and the power management device, and the third static and dynamic plug-in is connected between the main switch and the coil of the intermediate relay.

[0015] In a possible design, the sampled current loop further includes a fourth static and dynamic plug-in and a fifth static and dynamic plug-in. The fourth static and dynamic plug-in is connected between one end of the normally closed contact of the intermediate relay and the first terminal of the power control element, and the fifth static and dynamic plug-in is connected between the other end of the normally closed contact of the intermediate relay and the second terminal of the power control element.

[0016] Second aspect, the present invention provides a power quality management system, characterized in that it includes the sampling current circuit described in any one of the above, and also includes the current transformer and the power management device.

[0017] In a possible design, multiple groups of sampling current circuits are provided, the normally closed contacts of the intermediate relays in the multiple groups of sampling current circuits are connected in series, and multiple groups of power management devices are also provided, and the multiple groups of power management devices are arranged in one-to-one correspondence with the multiple groups of sampling current circuits.

[0018] The beneficial effects of the present invention are as follows:

[0019] The present invention discloses a sampling current circuit and a power quality management system, which can realize the automatic short-circuit of the secondary side of the current transformer and have strong safety. Specifically, in the implementation process of the present invention, the power management device is connected to the power supply and the current transformer through the present invention. When the main switch is closed, the power management device and the coil of the intermediate relay are energized, the normally closed contact of the intermediate relay is disconnected, and the power management device can receive the current signal transmitted by the current transformer through the power control element; when maintenance or testing is required for the power management device, the main switch can be disconnected, and at the same time, the power-off of the power management device and the short-circuit of the secondary side of the current transformer can be realized. Specifically, when the main switch is disconnected, the power management device and the coil of the intermediate relay lose power, the normally closed contact of the intermediate relay closes, and the secondary winding of the current transformer is short-circuited, thereby avoiding the danger of the current transformer operating open-circuit, and at the same time, through the automatic short-circuit of the secondary side of the current transformer, the safety of maintenance and repair personnel is ensured.

[0020] Other beneficial effects of the present invention will be further described in the specific implementation manner. Description of the Drawings

[0021] Figure 1 is the circuit schematic diagram of a sampling current circuit exemplified in Embodiment 1;

[0022] Figure 2 is the circuit schematic diagram of another sampling current circuit exemplified in Embodiment 1;

[0023] Figure 3 is the circuit schematic diagram of the power quality management system exemplified in Embodiment 2. Specific Embodiment

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the present invention in combination with the accompanying drawings and the description of the embodiments or the prior art. Obviously, the following description of the structures of the accompanying drawings is only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings. It should be noted here that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation to the present invention.

[0025] It should be understood that although terms such as first and second may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, the first unit can be called the second unit, and similarly, the second unit can be called the first unit, without departing from the scope of the exemplary embodiments of the present invention.

[0026] Embodiment 1:

[0027] This embodiment discloses a sampling current loop, which may but is not limited to include an intermediate relay KC and a main switch. One end of the normally closed contact of the intermediate relay KC is connected to the first terminal of the secondary winding of the current transformer CT, and the other end of the normally closed contact of the intermediate relay KC is connected to the second terminal of the secondary winding of the current transformer CT. One end of the normally closed contact of the intermediate relay KC is also connected to the first terminal of the power control element in the power management device, and the other end of the normally closed contact of the intermediate relay KC is also connected to the second terminal of the power control element. The coil of the intermediate relay KC and the power management device are both connected to the power supply through the main switch.

[0028] It should be understood that in this embodiment, the sampling current loop is used to receive the current signal collected by the current transformer CT, and after being processed such as signal conditioning and conversion, it can be transmitted to the power management device. In addition, in this embodiment, the current transformer CT is installed on the main circuit, and the current transformer CT is used to collect the current signal from the main circuit. The collected current signal can be converted into a small current signal suitable for the processing of secondary equipment and transmitted to components such as the power control element in the power management device through the secondary winding of the current transformer CT.

[0029] In this embodiment, the power supply is used to provide power support for the coil of the intermediate relay KC and the power management device. Specifically, in this embodiment, one end of the coil of the intermediate relay KC and the power management device are both connected to the main busbar through the main switch, and the other end of the coil of the intermediate relay KC is connected to the N wire. Among them, the main busbar is used to distribute three-phase electricity, and the N wire is used to provide a zero-potential reference. The two work together to complete power distribution. One end of the coil of the intermediate relay KC is connected to the main busbar through the main switch, and the other end is connected to the N wire to form a loop.

[0030] This embodiment can achieve automatic short-circuiting of the secondary side of the current transformer, with strong safety. Specifically, during the implementation of this embodiment, the power management device is connected to the power supply and the current transformer CT through this embodiment. When the main switch is closed, the power management device and the coil of the intermediate relay KC are powered on, and the normally closed contact of the intermediate relay KC is disconnected. The power management device can receive the current signal transmitted by the current transformer CT through the power control element; when maintenance or testing of the power management device is required, the power supply of the power management device and the short-circuiting of the secondary side of the current transformer CT can be achieved simultaneously by disconnecting the main switch. Specifically, when the main switch is disconnected, the power management device and the coil of the intermediate relay KC lose power, the normally closed contact of the intermediate relay KC closes, and the secondary winding of the current transformer CT is short-circuited, thereby avoiding the danger of open-circuit operation of the current transformer and ensuring the safety of maintenance and repair personnel through the automatic short-circuiting of the secondary side of the current transformer.

[0031] As Figure 1 shown, the main switch uses a load switch QL; correspondingly, the sampling current circuit further includes a first fuse FU1. The current input end of the main switch is connected to the power supply through the first fuse FU1, and the current output end of the main switch is connected to the coil of the intermediate relay KC and the power management device. It should be noted that the load switch QL is suitable for operations under normal working conditions, such as daily opening and closing operations, but usually does not have a protection function, that is, it cannot automatically respond to overload or short-circuit situations. Therefore, in this embodiment, the first fuse FU1 is equipped at the same time to achieve the protection of electrical equipment such as the intermediate relay KC and the power management device.

[0032] In this embodiment, the power management device uses a reactive power compensation device or a passive filtering device; correspondingly, the power control element uses a capacitor controller. It should be noted that in this kind of embodiment, the power management device is connected to Figure 1 the vertical main busbar in

[0033] It should be noted that the capacitor controller is used to automatically adjust the capacitor bank to ensure the stable operation of the power grid. When the power quality control device adopts a reactive power compensation device, the capacitor bank can be automatically adjusted through the capacitor controller to compensate reactive power and improve the power factor. When the power quality control device adopts a passive filter device, the capacitor controller can cooperate with the reactor to filter out harmonics and compensate reactive power.

[0034] In this embodiment, the sampling current loop further includes a second fuse FU2 and a lightning arrester FV. One end of the second fuse FU2 is connected to the junction of the coil of the intermediate relay KC and the main switch, and the other end of the second fuse FU2 is grounded through the lightning arrester FV. It should be noted that the second fuse FU2 and the lightning arrester FV can achieve the overcurrent protection and lightning protection functions of the power quality control device.

[0035] As Figure 2 shown, the main switch adopts a circuit breaker QF. It should be noted that the circuit breaker QF has multiple protection functions, including overload protection and short-circuit protection, and can automatically disconnect when a fault is detected to protect electrical equipment such as the intermediate relay KC and the power quality control device.

[0036] In this embodiment, the power quality control device adopts a static var generator SVG or an active power filter; correspondingly, the power control element adopts an AMK (Analog Measurement and Calculation Kit). It should be noted that the AMK is responsible for collecting current signals, performing arithmetic processing, and then outputting signals to the controller in the power quality control device. The controller can further output instructions to the power output unit in the power quality control device for compensation and filtering.

[0037] In this embodiment, the sampling current loop further includes a first static and dynamic plug-in CN1, a second static and dynamic plug-in CN2, and a third static and dynamic plug-in CN3. The first static and dynamic plug-in CN1 is connected between the main switch and the power supply, the second static and dynamic plug-in CN2 is connected between the main switch and the power quality control device, and the third static and dynamic plug-in CN3 is connected between the main switch and the coil of the intermediate relay KC.

[0038] In this embodiment, the sampling current loop further includes a fourth static and dynamic plug-in CN4 and a fifth static and dynamic plug-in CN5. The fourth static and dynamic plug-in CN4 is connected between one end of the normally closed contact of the intermediate relay KC and the first terminal of the power control element, and the fifth static and dynamic plug-in CN5 is connected between the other end of the normally closed contact of the intermediate relay KC and the second terminal of the power control element.

[0039] It should be noted that the settings of the first dynamic-static plug-in CN1, the second dynamic-static plug-in CN2, the third dynamic-static plug-in CN3, the fourth dynamic-static plug-in CN4, and the fifth dynamic-static plug-in CN5 can achieve the quick disassembly and assembly of related components, and are easy to perform operations such as component replacement.

[0040] Specifically, the working principle of this embodiment is as follows:

[0041] As Figure 1 shown, when the load switch QL is closed, the power quality management device is connected to the horizontal main busbar. The power quality management device and the coil of the intermediate relay KC are both connected to the power supply. The normally closed contact of the intermediate relay KC is disconnected, and the sampling current circuit is not short-circuited. At this time, the current signal circuit path is: S1 terminal of the current transformer CT -- XT terminal (XT: 1-XT: 6) -- sampling inlet of the capacitor controller (IA, IB, IC) -- sampling outlet of the capacitor controller (Ia, Ib, Ic) -- XT terminal (XT: 7-XT: 9) -- S2 terminal of the current transformer CT. When the load switch QL is opened, the power quality management device is disconnected from the horizontal main busbar. The power quality management device and the coil of the intermediate relay KC are both disconnected from the power supply. At this time, the normally closed contact of the intermediate relay KC is reset, and the sampling current circuit is short-circuited. At this time, the components in the power quality management device can be safely repaired without the risk of secondary open circuit of the current transformer. At this time, the current signal circuit path is: S1 terminal of the current transformer CT -- XT terminal (XT: 1-XT: 6) -- the terminal (10 / 11 / 12) of the intermediate relay KC -- XT terminal (XT: 7-XT: 11) -- S2 terminal of the current transformer CT.

[0042] As Figure 2 shown, when the circuit breaker QF is closed, the power quality management device is connected to the horizontal main busbar. The power quality management device and the coil of the intermediate relay KC are both connected to the power supply. The normally closed contact of the intermediate relay KC is disconnected, and the sampling current circuit is not short-circuited. At this time, the current signal circuit path is: S1 terminal of the current transformer CT -- XT terminal (XT: 1-XT: 6) -- SVG current sampling inlet -- SVG current sampling outlet -- XT terminal (XT: 7-XT: 11) -- S2 terminal of the current transformer CT; when the circuit breaker QF is opened, the power quality management device is disconnected from the horizontal main busbar. The power quality management device and the coil of the intermediate relay KC are both disconnected from the power supply. At this time, the normally closed contact of the intermediate relay KC is reset, and the sampling current circuit is short-circuited. Specifically, at this time, the current signal circuit path is: S1 terminal of the current transformer CT -- XT terminal (XT: 1-XT: 6) -- terminal (10 / 11 / 12) of the intermediate relay KC -- XT terminal (XT: 7-XT: 11) -- S2 terminal of the current transformer CT.

[0043] Embodiment 2:

[0044] This embodiment discloses a power quality management system, which includes a sampling current loop as described in Embodiment 1, and also includes the current transformer CT and the power management device.

[0045] Specifically, in this embodiment, multiple groups of sampling current loops are provided. The normally closed contacts of the intermediate relays KC in the multiple groups of sampling current loops are connected in series. Multiple groups of power management devices are also provided, and the multiple groups of power management devices are arranged in one-to-one correspondence with the multiple groups of sampling current loops.

[0046] As an example, as Figure 3 shown, the sampling current loop is set to five groups. The five groups of sampling current loops are divided into the first sampling current loop to the fifth sampling current loop connected in series in sequence. At this time, the working principle of the power quality management system is as follows:

[0047] When the first circuit breaker QF1 is closed, the first power management device is connected to the horizontal main busbar. The first power management device and the coil of the first intermediate relay KC1 are both connected to the power supply. At this time, the first intermediate relay KC1 is attracted, and the normally closed contact of the first intermediate relay KC1 is disconnected. The first sampling current loop is not short-circuited. When the second circuit breaker QF2 is closed, the power management device is connected to the horizontal main busbar. The second power management device and the coil of the second intermediate relay KC are both connected to the power supply. At this time, the second intermediate relay KC2 is attracted, and the normally closed contact of the second intermediate relay KC2 is disconnected. The second sampling current loop is not short-circuited. When the third circuit breaker QF3 is closed, the third power management device is connected to the horizontal main busbar. The third power management device and the coil of the third intermediate relay KC3 are both connected to the power supply. At this time, the third intermediate relay KC3 is attracted, and the normally closed contact of the third intermediate relay KC3 is disconnected. The third sampling current loop is not short-circuited. When the fourth circuit breaker QF4 is closed, the fourth power management device is connected to the horizontal main busbar. The fourth power management device and the coil of the fourth intermediate relay KC4 are both connected to the power supply. At this time, the fourth intermediate relay KC4 is attracted, and the normally closed contact of the fourth intermediate relay KC4 is disconnected. The fourth sampling current loop is not short-circuited. When the fifth circuit breaker QF5 is closed, the fifth power management device is connected to the horizontal main busbar. The fifth power management device and the coil of the fifth intermediate relay KC5 are both connected to the power supply. At this time, the fifth intermediate relay KC5 is attracted, and the normally closed contact of the fifth intermediate relay KC5 is disconnected. The fifth sampling current loop is not short-circuited;

[0048] The current signal loop path at this time is: S1 terminal of current transformer CT -- XT terminals (XT:1 - XT:6) -- current sampling inlet of AMK1 -- current sampling outlet of AMK1 -- XT terminals (XT:7 - XT:11) -- current sampling inlet of AMK2 -- current sampling outlet of AMK2 -- XT terminals (XT:13 - XT:17) -- current sampling inlet of AMK3 --- current sampling outlet of AMK3 -- XT terminals (XT:19 - XT:23) -- current sampling inlet of AMK4 -- sampling outlet of AMK4 -- XT terminals (XT:25 - XT:29) -- current sampling inlet of AMK5 -- current sampling outlet of AMK5 -- XT terminals (XT:31 - XT:35) -- S2 terminal of current transformer CT.

[0049] When the first circuit breaker QF1 opens, the first power management device is disconnected from the horizontal main busbar. The coils of both the first power management device and the first intermediate relay KC1 are disconnected from the power supply. At this time, the first intermediate relay KC1 resets, the normally closed contacts of the first intermediate relay KC1 reset, and the first sampling current loop is short - circuited. When the second circuit breaker QF2 closes, the second power management device is connected to the horizontal main busbar. The coils of both the second power management device and the second intermediate relay KC2 are connected to the power supply. At this time, the second intermediate relay KC2 is energized, the normally closed contacts of the second intermediate relay KC2 open, and the second sampling current loop is not short - circuited. When the third circuit breaker QF3 closes, the third power management device is connected to the horizontal main busbar. The coils of both the third power management device and the third intermediate relay KC3 are connected to the power supply. At this time, the third intermediate relay KC3 is energized, the normally closed contacts of the third intermediate relay KC3 open, and the third sampling current loop is not short - circuited. When the fourth circuit breaker QF4 closes, the fourth power management device is connected to the horizontal main busbar. The coils of both the fourth power management device and the fourth intermediate relay KC4 are connected to the power supply. At this time, the fourth intermediate relay KC4 is energized, the normally closed contacts of the fourth intermediate relay KC4 open, and the fourth sampling current loop is not short - circuited. When the fifth circuit breaker QF5 closes, the fifth power management device is connected to the horizontal main busbar. The coils of both the fifth power management device and the fifth intermediate relay KC5 are connected to the power supply. At this time, the fifth intermediate relay KC5 is energized, the normally closed contacts of the fifth intermediate relay KC5 open, and the fifth sampling current loop is not short - circuited;

[0050] At this time, the current signal loop path is as follows: S1 terminal of current transformer CT -- XT terminals (XT:1 - XT:6) -- terminals of intermediate relay KC1 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:7 - XT:11) -- current sampling inlet of AMK2 -- current sampling outlet of AMK2 -- XT terminals (XT:13 - XT:17) -- current sampling inlet of AMK3 -- current sampling outlet of AMK3 -- XT terminals (XT:19 - XT:23) -- current sampling inlet of AMK4 -- current sampling outlet of AMK4 -- XT terminals (XT:25 - XT:29) -- current sampling inlet of AMK5 -- current sampling outlet of AMK5 -- XT terminals (XT:31 - XT:35) -- S2 terminal of current transformer CT;

[0051] When the first circuit breaker QF1 trips, the first power quality management device disconnects from the horizontal main busbar, and the primary power supply of the first power quality management device is disconnected. At this time, the first intermediate relay KC1 resets, the normally closed contacts of the first intermediate relay KC1 reset, and the first sampling current loop is short - circuited. When the second circuit breaker QF2 trips, the second power quality management device disconnects from the horizontal main busbar, and the primary power supply of the second power quality management device is disconnected. At this time, the second intermediate relay KC2 resets, the normally closed contacts of the second intermediate relay KC2 reset, and the second sampling current loop is short - circuited. When the third circuit breaker QF3 closes, the third power quality management device is connected to the horizontal main busbar, and both the third power quality management device and the coil of the third intermediate relay KC3 are connected to the power supply. At this time, the third intermediate relay KC3 pulls in, the normally closed contacts of the third intermediate relay KC3 disconnect, and the third sampling current loop is not short - circuited. When the fourth circuit breaker QF4 closes, the fourth power quality management device is connected to the horizontal main busbar, and both the fourth power quality management device and the coil of the fourth intermediate relay KC4 are connected to the power supply. At this time, the fourth intermediate relay KC4 pulls in, the normally closed contacts of the fourth intermediate relay KC4 disconnect, and the fourth sampling current loop is not short - circuited. When the fifth circuit breaker QF5 closes, the fifth power quality management device is connected to the horizontal main busbar, and both the fifth power quality management device and the coil of the fifth intermediate relay KC5 are connected to the power supply. At this time, the fifth intermediate relay KC5 pulls in, the normally closed contacts of the fifth intermediate relay KC5 disconnect, and the fifth sampling current loop is not short - circuited;

[0052] The current signal loop path at this time is: S1 terminal of current transformer CT -- XT terminals (XT:1 - XT:6) -- terminals of intermediate relay KC1 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:7 - XT:11) -- terminals of second intermediate relay KC2 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:13 - XT:17) -- current sampling inlet of AMK3 -- current sampling outlet of AMK3 -- XT terminals (XT:19 - XT:23) -- current sampling inlet of AMK4 -- current sampling outlet of AMK4 -- XT terminals (XT:25 - XT:29) -- current sampling inlet of AMK5 -- current sampling outlet of AMK5 -- XT terminals (XT:31 - XT:35) -- S2 terminal of current transformer CT;

[0053] When the first circuit breaker QF1 trips, the first power quality management device disconnects from the horizontal main busbar, and both the first power quality management device and the coil of the first intermediate relay KC1 are disconnected from the power supply. At this time, the first intermediate relay KC1 resets, the normally closed contacts of the first intermediate relay KC1 reset, and the first sampling current loop is short-circuited. When the second circuit breaker QF2 trips, the second power quality management device disconnects from the horizontal main busbar, and the primary power supply of the second power quality management device is disconnected. At this time, the second intermediate relay KC2 resets, the normally closed contacts of the second intermediate relay KC2 reset, and the second sampling current loop is short-circuited. When the third circuit breaker QF3 trips, the third power quality management device disconnects from the horizontal main busbar, and the primary power supply of the third power quality management device is disconnected. At this time, the third intermediate relay KC3 resets, the normally closed contacts of the third intermediate relay KC3 reset, and the third sampling current loop is short-circuited. When the fourth circuit breaker QF4 closes, the fourth power quality management device is connected to the horizontal main busbar, and both the fourth power quality management device and the coil of the fourth intermediate relay KC4 are connected to the power supply. At this time, the fourth intermediate relay KC4 is energized, the normally closed contacts of the fourth intermediate relay KC4 open, and the fourth sampling current loop is not short-circuited. When the fifth circuit breaker QF5 closes, the fifth power quality management device is connected to the horizontal main busbar, and both the fifth power quality management device and the coil of the fifth intermediate relay KC5 are connected to the power supply. At this time, the fifth intermediate relay KC5 is energized, the normally closed contacts of the fifth intermediate relay KC5 open, and the fifth sampling current loop is not short-circuited;

[0054] The current signal loop path at this time is: S1 terminal of current transformer CT -- XT terminals (XT:1 - XT:6) -- terminals of intermediate relay KC1 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:7 - XT:11) -- terminals of intermediate relay KC2 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:13 - XT:17) -- terminals of intermediate relay KC3 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:19 - XT:23) -- current sampling inlet of AMK4 -- current sampling outlet of AMK4 -- XT terminals (XT:25 - XT:29) -- current sampling inlet of AMK5 -- current sampling outlet of AMK5 -- XT terminals (XT:31 - XT:35) -- S2 terminal of current transformer CT;

[0055] When the first circuit breaker QF1 trips, the first power management device disconnects from the horizontal main busbar, and both the first power management device and the coil of the first intermediate relay KC1 are disconnected from the power supply. At this time, the first intermediate relay KC1 resets, the normally closed contacts of the first intermediate relay KC1 reset, and the first sampling current loop is short - circuited. When the second circuit breaker QF2 trips, the second power management device disconnects from the horizontal main busbar, and the primary power supply of the second power management device is disconnected. At this time, the second intermediate relay KC2 resets, the normally closed contacts of the second intermediate relay KC2 reset, and the second sampling current loop is short - circuited. When the third circuit breaker QF3 trips, the third power management device disconnects from the horizontal main busbar, and both the third power management device and the coil of the third intermediate relay KC3 are disconnected from the power supply. At this time, the third intermediate relay KC3 resets, the normally closed contacts of the third intermediate relay KC3 reset, and the third sampling current loop is short - circuited. When the fourth circuit breaker QF4 trips, the fourth power management device disconnects from the horizontal main busbar, and both the fourth power management device and the coil of the fourth intermediate relay KC4 are disconnected from the power supply. At this time, the fourth intermediate relay KC4 resets, the normally closed contacts of the fourth intermediate relay KC4 reset, and the fourth sampling current loop is short - circuited. When the fifth circuit breaker QF5 closes, the fifth power management device connects to the horizontal main busbar, and both the fifth power management device and the coil of the fifth intermediate relay KC5 are connected to the power supply. At this time, the fifth intermediate relay KC5 pulls in, the normally closed contacts of the fifth intermediate relay KC5 open, and the fifth sampling current loop is not short - circuited;

[0056] At this time, the current signal loop path is as follows: terminal S1 of current transformer CT -- XT terminals (XT:1 - XT:6) -- terminals of intermediate relay KC1 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:7 - XT:11) -- terminals of intermediate relay KC2 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:13 - XT:17) -- terminals of intermediate relay KC3 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:19 - XT:23) -- terminals of intermediate relay KC4 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:25 - XT:29) -- current sampling inlet of AMK5 -- current sampling outlet of AMK5 -- XT terminals (XT:31 - XT:35) -- terminal S2 of current transformer CT;

[0057] When the first circuit breaker QF1 trips, the first power management device disconnects from the horizontal main busbar. The first power management device and the coil of the first intermediate relay KC1 are both disconnected from the power supply. At this time, the first intermediate relay KC1 resets, the normally closed contacts of the first intermediate relay KC1 reset, and the first sampling current loop is short-circuited. When the second circuit breaker QF2 trips, the second power management device disconnects from the horizontal main busbar. The power management device and the coil of the second intermediate relay KC2 are both disconnected from the power supply. At this time, the second intermediate relay KC2 resets, the normally closed contacts of the second intermediate relay KC2 reset, and the second sampling current loop is short-circuited. When the third circuit breaker QF3 trips, the third power management device disconnects from the horizontal main busbar. The third power management device and the coil of the third intermediate relay KC3 are both disconnected from the power supply. At this time, the third intermediate relay KC3 resets, the normally closed contacts of the third intermediate relay KC3 reset, and the third sampling current loop is short-circuited. When the fourth circuit breaker QF4 trips, the fourth power management device disconnects from the horizontal main busbar. The fourth power management device and the coil of the fourth intermediate relay KC4 are both disconnected from the power supply. At this time, the fourth intermediate relay KC4 resets, the normally closed contacts of the fourth intermediate relay KC4 reset, and the fourth sampling current loop is short-circuited. When the fifth circuit breaker QF5 trips, the fifth power management device disconnects from the horizontal main busbar. The fifth power management device and the coil of the fifth intermediate relay KC5 are both disconnected from the power supply. At this time, the fifth intermediate relay KC5 resets, the normally closed contacts of the fifth intermediate relay KC5 reset, and the fifth sampling current loop is short-circuited;

[0058] The current signal loop path at this time is: the S1 terminal of the current transformer CT -- XT terminals (XT:1 - XT:6) -- the terminals of the intermediate relay KC1 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:7 - XT:11) -- the terminals of the intermediate relay KC2 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:13 - XT:17) -- the terminals of the intermediate relay KC3 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:19 - XT:23) -- the terminals of the intermediate relay KC4 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:25 - XT:29) -- the terminals of the intermediate relay KC5 (2 / 3 / 4, 10 / 11 / 12) -- XT terminals (XT:31 - XT:35) -- the S2 terminal of the current transformer CT.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sampling current loop, characterized in that: It includes an intermediate relay (KC) and a main switch, wherein one end of the normally closed contact of the intermediate relay (KC) is connected to the first terminal of the secondary winding of the current transformer (CT), and the other end of the normally closed contact of the intermediate relay (KC) is connected to the second terminal of the secondary winding of the current transformer (CT). One end of the normally closed contact of the intermediate relay (KC) is also connected to the first terminal of the power control element in the power management device, and the other end of the normally closed contact of the intermediate relay (KC) is also connected to the second terminal of the power control element. The coil of the intermediate relay (KC) and the power management device are both connected to the power supply through the main switch.

2. A sampling current loop according to claim 1, characterized in that: The main switch adopts a load switch (QL); correspondingly, the sampling current loop also includes a first fuse (FU1), the current input end of the main switch is connected to the power supply through the first fuse (FU1), and the current output end of the main switch is connected to the coil of the intermediate relay (KC) and the electric energy management device.

3. A sampling current loop according to claim 1, characterized in that: The electric energy management device adopts a reactive compensation device or a passive filtering device; correspondingly, the electric energy control element adopts a capacitor controller.

4. A sampling current loop according to claim 3, characterized in that: The sampling current loop also includes a second fuse (FU2) and a lightning arrester (FV), one end of the second fuse (FU2) is connected to the junction of the coil of the intermediate relay (KC) and the main switch, and the other end of the second fuse (FU2) is grounded through the lightning arrester (FV).

5. A sampling current loop according to claim 1, characterized in that: The main switch is a circuit breaker (QF).

6. A sampling current loop according to claim 1, characterized in that: The electric energy management device adopts a static VAR generator (SVG) or an active power filter; correspondingly, the electric energy control element adopts an AMK.

7. A sampling current loop according to claim 1, characterized in that: The sampling current loop also includes a first dynamic-static plug-in (CN1), a second dynamic-static plug-in (CN2) and a third dynamic-static plug-in (CN3), wherein the first dynamic-static plug-in (CN1) is connected between the main switch and the power supply, the second dynamic-static plug-in (CN2) is connected between the main switch and the electric energy management device, and the third dynamic-static plug-in (CN3) is connected between the main switch and the coil of the intermediate relay (KC).

8. A sampling current loop according to claim 1, characterized in that: The sampling current loop also includes a fourth dynamic-static plug-in (CN4) and a fifth dynamic-static plug-in (CN5), wherein the fourth dynamic-static plug-in (CN4) is connected between one end of the normally closed contact of the intermediate relay (KC) and the first terminal of the electric energy control element, and the fifth dynamic-static plug-in (CN5) is connected between the other end of the normally closed contact of the intermediate relay (KC) and the second terminal of the electric energy control element.

9. A power quality management system, characterized in that: It comprises the sampling current loop as described in any one of claims 1 to 8, and also comprises the current transformer (CT) and the electric energy management device.

10. A power quality management system according to claim 9, characterized in that: The sampling current loop is provided with multiple groups, and the normally closed contacts of the intermediate relay (KC) in the multiple sampling current loops are connected in series. The electric energy management device is also provided with multiple groups, and the multiple groups of electric energy management devices are arranged one by one with the multiple sampling current loops.

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