Three-phase system PEN broken line detection circuit and sampling system
By designing a three-phase system PEN disconnection detection circuit and sampling system, the problem of high cost of PEN disconnection fault detectors in the prior art is solved and the problem of difficult conversion into TT system is difficult to achieve, and low-cost and flexible PEN disconnection is achieved. Fault detection function.
Patent Information
- Application Number
- CN202411654454.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-19
- Publication Date
- 2025-02-18
AI Technical Summary
In the prior art, the cost of PEN disconnection fault detector is high, and conversion into a TT system requires independent grounding poles, which is difficult to achieve in urban environments.
A three-phase system PEN disconnection detection circuit and sampling system is designed, including main control circuit, input module, relay control module, PEN acquisition module, relay feedback module, etc., to detect the relay status by collecting PEN line voltage and current signals in real time , realize the detection and handling of PEN line breakage faults.
It realizes low-cost PEN line break fault detection, with higher flexibility and scalability, avoids the need for additional installation of "overvoltage protectors" and reduces production and installation and maintenance costs.
Smart Images
Figure CN119471478A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of smart grids, and in particular to a three-phase system PEN disconnection detection circuit and a sampling system. Background Art
[0002] Smart grid, also known as "grid 2.0" or smart energy grid, smart power system, is built on the basis of integrated, high-speed two-way communication network. Through the application of advanced sensing and measurement technology, equipment technology, control method and decision support system technology, it realizes the goals of reliable, safe, economical, efficient, environmentally friendly and safe use of power grid. From a technical point of view, smart grid is an important application of Internet of Things, covering all aspects of power system power generation, transformation, distribution, transmission, power consumption and dispatching, covering all voltage levels, and realizing a highly integrated fusion of "power flow, information flow and business flow".
[0003] The grounding system of the British power grid is the PME system (TN-CS or TN-C), which requires PEN line break fault detection. The common practice of existing PEN line break detection is to install a "PEN fault line break monitoring protector" to achieve PEN line break fault detection, or install a "PEN fault line break monitoring protector" or use a TT system to convert it into a TT system. There are two ways, one is to set up a local TT system at the charging pile, and the other is to use a TT system for the entire system including the charging pile.
[0004] The above-mentioned prior art includes the installation of a "PEN fault disconnection monitoring protector" to cut off the connection between the phase conductor and the PE conductor and the electric vehicle charging facility when the voltage (contact voltage) between the PE conductor and the ground at the charging point exceeds 70V. The installation of the "PEN fault disconnection monitoring protector" means that after the PEN is disconnected, the neutral point position depends on the three-phase imbalance of the user and the power grid. From the perspective of the vector diagram, the distance from the drifted neutral point N' to the center point N (original neutral point) of the original voltage vector triangle is the contact voltage. The function of the phase voltage monitor is to disconnect the power supply before the three-phase imbalance causes a dangerous contact voltage (such as 70V).
[0005] The above-mentioned prior art has the following major disadvantages: 1. The cost of "PEN fault disconnection monitoring protector" or "overvoltage and undervoltage protector" is relatively high; 2. Conversion to TT system requires the establishment of an independent grounding electrode, which is difficult to achieve the independent grounding device required by the TT system in cities with numerous buildings. Summary of the invention
[0006] The object of the present invention is to provide a three-phase system PEN line break detection circuit and sampling system to solve the problems raised in the above background technology: 1. The cost of "PEN fault line break monitoring protector" or "overvoltage and undervoltage protector" is relatively high; 2. Conversion to a TT system requires the establishment of an independent grounding electrode, and it is difficult to achieve the independent grounding device required by the TT system in a city with numerous buildings.
[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a three-phase system PEN disconnection detection circuit and sampling system, including a main control circuit, an input module, a relay control module, a PEN acquisition module, a relay feedback module, a relay coil module, a relay main contact module, a relay auxiliary contact module and an output module, wherein the input module includes an input PE, an input N, an input L1, an input L2, and an input L3; The main control circuit is electrically connected to the relay control module, the PEN acquisition module, and the relay feedback module through the input module, and the relay control module, the PEN acquisition module, and the relay feedback module correspond to the relay coil module, the relay main contact module, and the relay auxiliary contact module respectively, and the relay coil module, the relay main contact module, and the relay auxiliary contact module all correspond to the output module.
[0008] Preferably, the input PE corresponds to the PEN acquisition module, corresponds to the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
[0009] Preferably, the input N corresponds to a relay coil module, a relay main contact module, and a relay auxiliary contact module. In this process, a relay control module and a relay feedback module exist between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
[0010] Preferably, the input L1 corresponds to the PEN acquisition module, corresponds to the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
[0011] Preferably, the input L2 corresponds to the PEN acquisition module, corresponds to the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
[0012] Preferably, the input L3 corresponds to the PEN acquisition module, corresponds to the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
[0013] Compared with the prior art, the beneficial effects achieved by the present invention are: First, the present invention can replace the "over-voltage and under-voltage protector" solution at a low cost, has higher flexibility and stronger scalability, eliminates the need for additional installation of "over-voltage and under-voltage protectors", reduces production costs, and also reduces installation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 is the neutral point drift vector diagram of the present invention; Figure 2 This is the AD sampling diagram of the present invention; Figure 3 This is a system block diagram of the present invention. DETAILED DESCRIPTION
[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0016] See also Figure 1 , 2 and Figure 3 , a three-phase system PEN disconnection detection circuit and sampling system, including a main control circuit, an input module, a relay control module, a PEN acquisition module, a relay feedback module, a relay coil module, a relay main contact module, a relay auxiliary contact module and an output module, characterized in that: the input module includes an input PE, an input N, an input L1, an input L2, and an input L3; The main control circuit is electrically connected to the relay control module, the PEN acquisition module, and the relay feedback module through the input module, and the relay control module, the PEN acquisition module, and the relay feedback module correspond to the relay coil module, the relay main contact module, and the relay auxiliary contact module respectively, and the relay coil module, the relay main contact module, and the relay auxiliary contact module all correspond to the output module.
[0017] In this embodiment, the main control circuit: as the core of the entire system, is responsible for receiving input signals, processing data, and controlling the work of other modules; the input module: includes multiple input endpoints, such as PE (protective grounding wire), N (neutral wire), L1, L2, L3 (three-phase live wire), and these input endpoints are used to receive voltage and current signals from the power grid; the relay control module: controls the coil module of the relay according to the instructions of the main control circuit, and then controls the state of the relay main contact module and the relay auxiliary contact module; the PEN acquisition module: is specifically used to collect voltage and current signals on the PEN line (shared by the working neutral line and the protective neutral line), and transmit these signals to the main control circuit for processing; the relay feedback module: is used to detect the state of the relay and feed back the state information to the main control circuit, so that the main control circuit can make corresponding control decisions based on this information; the relay coil module, the relay main contact module, and the relay auxiliary contact module: these modules together constitute the relay, which is used to cut off or close the circuit when the PEN line is detected to be broken or other faults, so as to protect the safety of equipment and personnel; the output module: is used to output the working state, fault information, etc. of the system to external equipment or users for monitoring and maintenance.
[0018] In this embodiment, the system is characterized in that it can timely detect and handle PEN line disconnection or other faults by real-time acquisition of voltage and current signals on the PEN line and detection of the state of the relay, thereby ensuring the stable operation of the power grid and protecting the safety of equipment and personnel. This design is of great significance for improving the reliability, safety and intelligence level of the power grid.
[0019] Specifically, the input PE corresponds to the PEN acquisition module, which corresponds to the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
[0020] In this embodiment, the system receives the PE (protective earth) input from the power grid, and this input PE is connected to the PEN acquisition module. The function of the PEN acquisition module is to monitor and collect the voltage and current signals on the PE (also known as PEN, when PE and N are combined) line in real time, and the collected data will be transmitted to the main control circuit for processing. The main control circuit determines whether the PEN line is disconnected or other abnormal conditions occur according to the status of these signals and the preset logic. When the main control circuit detects an abnormal situation and needs to take action, it will send a control signal to the relay coil module through the relay control module. The relay control module is an intermediary. It adjusts the control voltage or current of the relay coil module according to the instructions of the main control circuit, thereby controlling the action of the relay. After receiving the control signal, the relay coil module will cause physical action inside the relay according to the type of signal (for example: closed or open), which will cause the status of the relay main contact module and the relay auxiliary contact module to change. The main contact module is usually used to control the on and off of the main circuit, while the auxiliary contact module is used to provide feedback signals to the relay feedback module. The function of the relay feedback module is to detect the status of the relay main contact module or the auxiliary contact module, and feed back this status information to the main control circuit. In this way, the main control circuit can understand the status of the relay in real time, thereby ensuring that the system works as expected.
[0021] Specifically, the input N corresponds to the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
[0022] In this embodiment, when the voltage or state of input N changes, the main control circuit receives a corresponding signal, and then the main control circuit sends a control signal to the relay coil module through the relay control module. After receiving the control signal, the relay coil module energizes or de-energizes the coil inside the relay according to the instruction of the signal, thereby controlling the closing or opening of the relay main contact module. The relay main contact module is usually used to control the on and off of the main circuit. When the main contact is closed, the main circuit is energized; when the main contact is disconnected, the main circuit is cut off. In this way, by controlling the on and off state of the relay main contact module, the main control circuit can achieve effective control of the main circuit. At the same time, the relay auxiliary contact The module will also undergo corresponding changes when the relay is actuated. The auxiliary contacts are usually used to provide feedback signals to the relay feedback module. When the relay main contact module is closed or disconnected, the auxiliary contacts will also be closed or disconnected accordingly, thereby sending a feedback signal to the relay feedback module. After receiving the feedback signal, the relay feedback module will transmit it to the main control circuit. The main control circuit will confirm whether the relay main contact module has performed the on-off operation according to the instruction based on this feedback signal. If everything is normal, the main control circuit will continue to perform other tasks; if there is a problem (such as the relay main contact module fails to perform the on-off operation according to the instruction), the main control circuit will take corresponding measures to deal with this abnormal situation.
[0023] Specifically, the input L1 corresponds to the PEN acquisition module, the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
[0024] Specifically, the input L2 corresponds to the PEN acquisition module, the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
[0025] Specifically, the input L3 corresponds to the PEN acquisition module, the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
[0026] In this embodiment, a low-cost PEN disconnection fault detection function is realized by equivalently replacing the "over-voltage and under-voltage protector". After the PEN is disconnected, the neutral point position depends on the three-phase imbalance of the user and the power grid. From the perspective of the vector diagram, the distance from the drifted neutral point N' to the center point N (original neutral point) of the original voltage vector triangle is the contact voltage. Figure 1As shown in the figure, combined with the voltage transformer, the size of the contact voltage can be calculated through ADC sampling, so as to determine whether there is a PEN disconnection fault in the system. Figure 2 shown.
[0027] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A three-phase system PEN disconnection detection circuit and sampling system, comprising a main control circuit, an input module, a relay control module, a PEN acquisition module, a relay feedback module, a relay coil module, a relay main contact module, a relay auxiliary contact module and an output module, characterized in that: The input module includes input PE, input N, input L1, input L2, and input L3; The main control circuit is electrically connected to the relay control module, the PEN acquisition module, and the relay feedback module through the input module, and the relay control module, the PEN acquisition module, and the relay feedback module correspond to the relay coil module, the relay main contact module, and the relay auxiliary contact module respectively, and the relay coil module, the relay main contact module, and the relay auxiliary contact module all correspond to the output module.
2. A three-phase system PEN disconnection detection circuit and sampling system according to claim 1, characterized in that: The input PE corresponds to the PEN acquisition module, corresponds to the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
3. A three-phase system PEN disconnection detection circuit and sampling system according to claim 1, characterized in that: The input N corresponds to a relay coil module, a relay main contact module, and a relay auxiliary contact module. In this process, a relay control module and a relay feedback module exist between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
4. A three-phase system PEN disconnection detection circuit and sampling system according to claim 1, characterized in that: The input L1 corresponds to the PEN acquisition module, the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
5. A three-phase system PEN disconnection detection circuit and sampling system according to claim 1, characterized in that: The input L2 corresponds to the PEN acquisition module, corresponds to the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.
6. A three-phase system PEN disconnection detection circuit and sampling system according to claim 1, characterized in that: The input L3 corresponds to the PEN acquisition module, which corresponds to the relay coil module, the relay main contact module, and the relay auxiliary contact module. In this process, there is a relay control module and a relay feedback module between the main control circuit and the relay coil module, the relay main contact module, and the relay auxiliary contact module.