A comprehensive relay protection measurement and control device

Abstract

The utility model relates to power system technical field, concretely is a kind of comprehensive relay protection measurement and control device, including control power supply anode and control power supply cathode, control power supply cathode connects closing command relay, the other end of closing command relay is sequentially connected line bypass contactor, small current protection relay and closing lockout relay, and closing lockout relay and control power supply anode constitute closing loop;Control power supply cathode connects opening command relay, and opening command relay is connected line bypass contactor and constitutes opening loop with control power supply anode;The secondary side output end of current transformer is electrically connected with the current signal input end of small current protection relay.In relay protection device, it is integrated with the special small current protection function, effectively coped with abnormal no-load, light load and other working conditions, solved the inherent defect that traditional device only pays attention to " overcurrent " and cannot identify " undercurrent " fault, filled the technical blank in this field.

Description

Technical Field

[0001] This utility model relates to the field of power system technology, specifically to an integrated relay protection and control device. Background Technology

[0002] The statements in this section merely provide background information related to this utility model and do not necessarily constitute prior art.

[0003] In power supply systems, relay protection devices are core equipment for ensuring the safe and stable operation of lines and equipment. Traditional line protection devices and transformer substation monitoring and control protection devices are primarily designed for fault protection of single-circuit high-voltage lines. Their core protection functions (such as the classic three-stage current protection) are focused on dealing with high-current fault scenarios such as overcurrent and short circuits. This type of protection falls under the category of "high-current protection," and its operating logic is to quickly disconnect the faulty line when the current exceeds a set threshold.

[0004] However, with the development of energy-saving technologies and the increasing application of specific scenarios (such as energy-saving systems for power collection lines and intelligent distribution cabinets), a new protection requirement has emerged: low-current protection. The purpose of this function is to monitor abnormally weak currents in the line. For example, when the system is in an abnormal no-load state, experiences a light-load fault, or an anomaly occurs during energy-saving mode switching, the line current may be significantly lower than the minimum safety threshold required for normal operation, thus triggering protection action. This "undercurrent" condition is also a system anomaly. If not handled promptly, it may lead to no-load losses in equipment, system control logic chaos, and even subsequent safety accidents such as power-on surges.

[0005] Existing protection devices are functionally limited, with their protection logic primarily focused on handling high-current faults and traditional automatic transfer switching (ATS) circuit logic controls. They generally lack dedicated monitoring and protection modules for the specific signal of "low current." Consequently, they cannot effectively identify the aforementioned abnormal no-load or light-load faults, nor can they issue correct protection action commands accordingly, making it difficult to meet the integrated and intelligent protection requirements of next-generation energy-saving systems. Utility Model Content

[0006] This invention provides a comprehensive relay protection and control device that solves the problem of existing technologies being unable to effectively monitor and respond to abnormal low-current conditions in power lines. By integrating multi-channel sampling and interlocking logic, this device can accurately identify low-current faults and reliably operate, preventing equipment malfunctions and accidents. It provides a dedicated, economical, and reliable protection solution for special applications such as energy-saving system cabinets.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: This utility model provides an integrated relay protection and control device, including a control power supply positive terminal (L+) and a control power supply negative terminal (M-), and further includes: The closing command relay (KA2) has one end of its coil connected to the negative terminal (M-) of the control power supply. The line bypass contactor (DL2) has its closing coil connected in series with the other end of the closing command relay (KA2) coil; The normally closed contact of the low current protection relay (KC1) is connected in series after the closing coil of the line bypass contactor (DL2); The normally closed contact of the closing lockout relay (KA1) is connected in series after the normally closed contact of the low current protection relay (KC1), and forms a closing circuit with the positive terminal (L+) of the control power supply. The tripping command relay (KA3) has one end of its coil connected to the negative terminal (M-) of the control power supply. The tripping coil of the line bypass contactor (DL2) is connected in series with the other end of the tripping command relay (KA3) coil, and forms a tripping circuit with the positive terminal (L+) of the control power supply. The secondary output terminal of the current transformer (TA1a) is electrically connected to the current signal input terminal of the small current protection relay (KC1).

[0008] Furthermore, the coil of the closing lockout relay (KA1) is connected in series with a normally open contact of the low current protection relay (KC1), and in parallel between the positive terminal (L+) and the negative terminal (M-) of the control power supply.

[0009] Furthermore, in the tripping circuit, at least two triggering branches are connected in parallel at the front end of the coil of the tripping command relay (KA3). The triggering branches include the branch where the tripping button (SB2) is located and the branch where another normally open contact of the low current protection relay (KC1) is located.

[0010] Furthermore, the triggering branch also includes the branch where the time-delayed normally open contact of the time relay (KT1) is located.

[0011] Furthermore, the coil of the time relay (KT1) is connected in series with a normally open auxiliary contact of the line bypass contactor (DL2), and then connected in parallel between the positive terminal (L+) and the negative terminal (M-) of the control power supply.

[0012] Furthermore, in the closing circuit, a manual closing branch and an automatic closing branch are connected in parallel in front of the normally closed contact of the closing interlocking relay (KA1); the manual closing branch is connected in series with the closing button (SB1), and the automatic closing branch is connected in series with the closing output contact of the line controller (ACC).

[0013] Furthermore, it also includes a control switch / selector switch (SA1), whose first pair of contacts (5-6) are used to connect or disconnect the manual closing branch from the positive terminal of the control power supply (L+), and whose second pair of contacts (7-8) are used to connect or disconnect the automatic closing branch from the positive terminal of the control power supply (L+).

[0014] Furthermore, the tripping circuit also includes a trigger branch connected in series with the tripping output contact of the line controller (ACC).

[0015] Furthermore, the normally open contact of the closing command relay (KA2) is connected in series in the drive circuit of the closing coil of the line bypass contactor (DL2).

[0016] Furthermore, the normally open contact of the trip command relay (KA3) is connected in series in the drive circuit of the trip coil of the line bypass contactor (DL2).

[0017] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects: 1. This solution integrates a dedicated low-current protection function into the relay protection device, which effectively addresses abnormal no-load and light-load conditions, solves the inherent defect of traditional devices that only focus on "overcurrent" and cannot identify "undercurrent" faults, and fills the technical gap in this field.

[0018] 2. By monitoring the line current in real time and taking immediate action when the current is below the safety threshold, this solution can promptly cut off abnormal operating conditions, effectively avoiding safety accidents such as control logic confusion, equipment damage, or subsequent power-on shocks that may be caused by abnormal states such as equipment no-load operation and energy-saving switching failure, greatly improving the reliability of the entire power supply system.

[0019] 3. It highly integrates low-current protection, traditional logic control (such as automatic transfer switch), and time-delay protection into a single device, providing a dedicated, integrated solution for specific application scenarios such as photovoltaic power collection lines and intelligent energy-saving system cabinets. This eliminates the need for external independent components, simplifies system design and wiring, and reduces overall complexity and cost.

[0020] 4. Key parameters of the device (such as low-current operating threshold and time delay protection time) can be set by the user according to actual operating conditions, enabling it to flexibly adapt to various application scenarios. This "tailor-made" protection strategy ensures safety while avoiding economic losses caused by over-protection or inadequate protection, providing a more economical protection solution. Attached Figure Description

[0021] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0022] Figure 1 This is a schematic diagram of the wiring principle of the integrated relay protection and control device provided by this utility model; Figure 2 This is a schematic diagram of the wiring principle of the low-current protection relay provided by this utility model. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] As described in the background section, when a system is in an abnormal no-load state, experiences a light-load fault, or encounters an anomaly during energy-saving mode switching, the line current will be significantly lower than the minimum safety threshold required for normal operation, thereby triggering protection actions. This "undercurrent" condition is also a system anomaly. If not handled in time, it may lead to no-load losses in equipment, system control logic chaos, and even subsequent safety accidents such as power-on surges.

[0026] Existing protection devices are functionally limited, with their protection logic primarily focused on handling high-current faults and traditional automatic transfer switching (ATS) circuit logic controls. They generally lack dedicated monitoring and protection modules for the specific signal of "low current." Consequently, they cannot effectively identify the aforementioned abnormal no-load or light-load faults, nor can they issue correct protection action commands accordingly, making it difficult to meet the integrated and intelligent protection requirements of next-generation energy-saving systems.

[0027] Therefore, this solution provides a comprehensive relay protection and control device that reverses the traditional "overcurrent protection" logic to create an "undercurrent protection" mechanism. It monitors the line current in real time via a current transformer, and when the current falls below a safe threshold, a relay triggers tripping and lockout. By deeply integrating low-current monitoring, time-relay control, and manual / automatic tripping / closing logic, a comprehensive protection and control system that accurately identifies low-current faults and operates reliably is constructed.

[0028] Figure 1 and Figure 2The switching devices in the circuit are as follows: SA1 control switch / selector switch, SB1 closing button, KA1 closing interlocking relay, KC1 low current protection relay, DL2 line bypass contactor, KA2 closing command relay, ACC line controller, SB2 opening button, KA3 opening command relay, KT1 time relay, TA1a current transformer, and N441 and A441 terminal blocks / cable numbers.

[0029] The names and functions of each component in the above circuit schematic are shown in Table 1.

[0030] Table 1. Device Name and Function Description

[0031] like Figure 1 As shown in the figure, this embodiment provides a comprehensive relay protection and control device, including a DC control power supply L+ and M-, with a closing command relay KA2 and a opening command relay KA3 connected in parallel on M-; The other end of the closing command relay KA2 is connected in series with the line bypass contactor DL2, the small current protection relay KC1 and the closing lockout relay KA1. The other end of the closing lockout relay KA1 is connected to the closing button SB1 and the line controller ACC respectively. The other end of the closing button SB1 is connected to node "6" of the control switch / selector switch SA1. The other end of the line controller ACC is connected to node "8" of the control switch / selector switch SA1. Nodes "5" and "7" of the control switch / selector switch SA1 are connected to L+. The other end of the tripping command relay KA3 is connected to the line bypass contactor DL2. The other end of the line bypass contactor DL2 is connected to the tripping button SB2, the low current protection relay KC1, the time relay KT1, and the line controller ACC. The other ends of the tripping button SB2 and the low current protection relay KC1 are connected between node "6" of the control switch / selector switch SA1 and the closing button SB1. The other ends of the time relay KT1 and the line controller ACC are connected to node "8" of the control switch / selector switch SA1.

[0032] One end of the low current protection relay KC1 is grounded through terminal block / cable N441, and the other end is connected to terminal block / cable A441, current transformer TA1a and terminal block / cable N441 in sequence before being grounded.

[0033] KC1 is a low-current protection relay, and Ta1A is a current transformer that monitors the current in real time. The monitored current value is transmitted to KC1 in real time, and KC1 makes a judgment on the low-current protection action. When the line current is higher than the set value (e.g., set to 2A), the system issues a low-current protection action.

[0034] When the photovoltaic power collection line needs to be closed, the bypass contactor is first activated to determine the low-current protection blocking conditions. The low-current protection setting value can be set by the user (e.g., 2A). When the low-current blocking meets the control requirements, the system immediately issues a closing command to the bypass contactor. After the bypass contactor is closed, if the low-current protection blocking is activated, the system immediately interlocks the bypass contactor.

[0035] In this scheme, node "5" of the control switch / selector switch SA1 is the "first node", node "6" is the "second node", node "7" is the "third node", and node "8" is the "fourth node".

[0036] The closing process is as follows: Manual closing (press SB1) or automatic closing (ACC issues a command).

[0037] Closing circuit: L+ → SA1(5-6) → KA1 (normally closed) → KA2 coil → M-. KA2 is energized.

[0038] The KA2 contact connects the closing circuit of DL2, and DL2 closes.

[0039] Lockout condition: If the low current protection KC1 has been activated, it will drive KA1 to close, and its normally closed contact will open, thereby cutting off the closing circuit and realizing "closing lockout".

[0040] Opening process: Manual tripping: Press SB2 to connect the KA3 circuit. KA3 will then trip DL2.

[0041] Low current protection tripping: If the current is too low during operation, KC1 will activate, and its contacts will directly or indirectly (such as through ACC) connect the KA3 circuit, triggering tripping.

[0042] Delayed protection tripping: After closing, KT1 starts timing. When the time is up, its contacts connect the KA3 circuit, triggering tripping.

[0043] Automatic tripping: The ACC issues a tripping command based on system logic (such as failure of automatic transfer switch).

[0044] Low current protection monitoring: The current transformer TA1a monitors the line current in real time and transmits the data to KC1.

[0045] KC1 compares the measured value with the set value (e.g., 2A). If the actual current is lower than the set value, KC1 determines it to be a fault (e.g., no-load, open circuit, abnormal energy-saving switching) and then takes action.

[0046] This solution integrates a dedicated low-current protection function into the relay protection device, effectively addressing abnormal no-load and light-load conditions. It solves the inherent defect of traditional devices that only focus on "overcurrent" and cannot identify "undercurrent" faults, filling a technological gap in this field.

[0047] By monitoring the line current in real time and taking swift action when the current falls below a safe threshold, this solution can promptly cut off abnormal operating conditions, effectively avoiding safety accidents such as control logic confusion, equipment damage, or subsequent power-on shocks that may be caused by abnormal states such as equipment no-load operation or energy-saving switching failure, thus greatly improving the reliability of the entire power supply system.

[0048] The device integrates multi-channel sampling and complex interlocking logic (such as enabling delay after closing and interlocking closing after low-current action), achieving refined management of protection strategies. This not only ensures accurate identification and reliable operation of low-current protection but also effectively distinguishes between normal tripping and fault protection, fundamentally preventing equipment maloperation and failure to operate.

[0049] The solution highly integrates functions such as low-current protection, traditional logic control (such as automatic transfer switch), and time-delay protection into a single device, providing a dedicated, integrated solution for specific application scenarios such as photovoltaic power collection lines and intelligent energy-saving system cabinets. This eliminates the need for external independent components, simplifies system design and wiring, and reduces overall complexity and cost.

[0050] Key parameters of the solution device (such as low current operating threshold and time delay protection time) can be set by the user according to actual operating conditions, making it flexibly adaptable to various application scenarios. This "tailor-made" protection strategy ensures safety while avoiding economic losses caused by over-protection or inadequate protection, providing a more economical protection solution.

[0051] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A comprehensive relay protection and control device, comprising a control power supply positive terminal (L+) and a control power supply negative terminal (M-), characterized in that, Also includes: The closing command relay (KA2) has one end of its coil connected to the negative terminal (M-) of the control power supply. The line bypass contactor (DL2) has its closing coil connected in series with the other end of the closing command relay (KA2) coil; The normally closed contact of the low current protection relay (KC1) is connected in series after the closing coil of the line bypass contactor (DL2); The normally closed contact of the closing lockout relay (KA1) is connected in series after the normally closed contact of the low current protection relay (KC1), and forms a closing circuit with the positive terminal (L+) of the control power supply. The tripping command relay (KA3) has one end of its coil connected to the negative terminal (M-) of the control power supply. The tripping coil of the line bypass contactor (DL2) is connected in series with the other end of the tripping command relay (KA3) coil, and forms a tripping circuit with the positive terminal (L+) of the control power supply. The secondary output terminal of the current transformer (TA1a) is electrically connected to the current signal input terminal of the small current protection relay (KC1).

2. The integrated relay protection and control device as described in claim 1, characterized in that, The coil of the closing lockout relay (KA1) is connected in series with a normally open contact of the small current protection relay (KC1), and is connected in parallel between the positive terminal (L+) and the negative terminal (M-) of the control power supply.

3. The integrated relay protection and control device as described in claim 1, characterized in that, In the tripping circuit, at least two triggering branches are connected in parallel at the front end of the coil of the tripping command relay (KA3). The triggering branches include the branch where the tripping button (SB2) is located and the branch where another normally open contact of the low current protection relay (KC1) is located.

4. The integrated relay protection and control device as described in claim 3, characterized in that, The tripping circuit also includes a trigger branch connected in series with the tripping output contact of the line controller (ACC).

5. The integrated relay protection and control device as described in claim 3, characterized in that, The triggering branch also includes the branch containing the delayed closing normally open contact of the time relay (KT1).

6. The integrated relay protection and control device as described in claim 5, characterized in that, The coil of the time relay (KT1) is connected in series with a normally open auxiliary contact of the line bypass contactor (DL2), and then connected in parallel between the positive terminal (L+) and the negative terminal (M-) of the control power supply.

7. The integrated relay protection and control device as described in claim 1, characterized in that, In the closing circuit, a manual closing branch and an automatic closing branch are connected in parallel at the front end of the normally closed contact of the closing interlocking relay (KA1); the manual closing branch is connected in series with the closing button (SB1), and the automatic closing branch is connected in series with the closing output contact of the line controller (ACC).

8. The integrated relay protection and control device as described in claim 7, characterized in that, It also includes a control switch / selector switch (SA1), which has a pair of contacts for connecting or disconnecting the manual closing branch and connecting it to the positive terminal (L+) of the control power supply, and another pair of contacts for connecting or disconnecting the automatic closing branch and connecting it to the positive terminal (L+) of the control power supply.

9. The integrated relay protection and control device as described in claim 1, characterized in that, The normally open contact of the closing command relay (KA2) is connected in series in the drive circuit of the closing coil of the line bypass contactor (DL2).

10. The integrated relay protection and control device as described in claim 1, characterized in that, The normally open contact of the trip command relay (KA3) is connected in series in the drive circuit of the trip coil of the line bypass contactor (DL2).

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