External alternating-current jumping-in trigger device

Abstract

The utility model relates to an external alternating-current jumping-in trigger device. Relates to a bus monitoring system. Comprising a power supply terminal which comprises a positive electrode end and a negative electrode end and is used for being connected with a corresponding positive bus and a corresponding negative bus in a direct-current bus; the signal receiving port is provided with a wiring terminal used for being externally connected with an insulation host and is used for receiving 485 signals sent by the insulation host and sending daily heartbeat messages; a signal receiving terminal of the time relay is connected to the signal receiving port, so that communication between the outside and the time relay is realized; the input end of the alternating current signal generator is connected with the time relay, the output end of the alternating current signal generator is connected with the signal receiving port, and the alternating current signal generator sends out low-frequency alternating current signals to serve as a signal source for alternating current entering. The insulation monitoring precision simulation device is of great significance to insulation monitoring precision simulation of the insulation host which operates for a long time.

Description

Technical Field

[0001] The utility model relates to a bus monitoring system, in particular to an external AC intrusion trigger device. Background Art

[0002] As an important power supply facility inside the substation, the stability of the power supply system determines the power supply quality of the substation. In the power supply system inside the substation, it is generally an integrated power supply system, and the DC power supply system in the integrated power supply system is an important component. Therefore, it is very necessary to monitor the DC power supply system in real time and send alarms. In recent years, with the continuous increase in power grid capacity, the installed capacity has also been continuously increasing. The total installed capacity of new energy substations such as photovoltaic and wind power has even reached hundreds of megawatts (MW). Therefore, the total capacity of the DC power supply system in the station also needs to be continuously increased, and the burden on the main monitoring DC system is also increasing. Therefore, it is necessary to strip the functions inside the main monitoring to form a special monitoring system for monitoring special contents, such as AC part monitoring, UPS part monitoring, battery part monitoring, etc., and finally upload the monitoring content to the main monitoring by summarizing it, so that the main monitoring will eventually become an integrated display but not participate in all controls. The display component retains some main functions such as floating charge control.

[0003] AC intrusion is an important monitoring object of the insulation system. The insulation system originally belonged to the DC system and is an important monitoring content when the DC power supply is working normally. Due to the continuous increase in installed capacity, the number of distribution boards and feeder branches under the distribution boards has continued to increase, resulting in an increase in the monitoring content of the insulation monitoring system, which has brought increasing pressure on the main monitoring. Therefore, most domestic manufacturers have separated the insulation monitoring system from the main monitoring and designed it into a separate insulation host for overall monitoring of the insulation condition of the DC power supply system.

[0004] In general, the insulation host will monitor the insulation condition of the current bus in real time. Its internal detection bridge and other switching will calculate the grounding resistance when DC mutual leakage and DC bus insulation grounding (DC grounding) occur. If the branch is grounded, the faulty branch will be accurately located through the branch grounding condition uploaded by the lower computer. However, when AC is injected into the system, the insulation host will use the AC injection as the only alarm and then eliminate DC mutual leakage and DC grounding. Under normal circumstances, the unbalanced bridge switching of the standard insulation host is allowed to be performed at most once a day, and the time should be fixed. As an important insulation monitoring part, the normal working performance of the insulation host must be verified and feasible during installation, and the integrity of the function must be ensured in future work. At present, the insulation host has the following main defects:

[0005] 1. The unbalanced bridge function of the insulation host on the market has been set at the factory. It uses switching once a day to test whether its internal function is faulty, and can detect insulation faults in the DC system during switching. However, it cannot be switched again before the next switching setting time after the switching is completed.

[0006] 2. The alarm level of AC inrush is the highest in the standard. When AC inrush occurs, the insulation host will theoretically shield all other insulation alarms such as DC grounding and DC mutual inrush. The specific reason is that when AC inrush occurs, the busbar insulation will inevitably decrease. At this time, it is necessary to monitor the basic characteristics such as the determined AC signal and its frequency to determine whether the busbar insulation has decreased due to AC inrush. The general insulation host will shield the other insulation alarms. If other insulation alarms really occur at this time, the host cannot report them. If the AC inrush signal monitoring is slow due to insulation system design problems, it may even cause the insulation host to falsely alarm, resulting in unnecessary losses.

[0007] 3. Long-term installation of the insulation host may cause aging of the device and eventually affect the monitoring ability of the insulation system. For accidental events such as AC intrusion, it is extremely important whether the insulation host that has been running for a long time can accurately report the alarm. Utility Model Content

[0008] In view of the above problems, the utility model provides an external AC inrush trigger device which has a delicate structure and clearly defines the insulation monitoring capability and insulation monitoring accuracy of an insulation host.

[0009] The technical solution of the utility model is:

[0010] External AC inrush trigger device, including:

[0011] A power terminal, including a positive terminal and a negative terminal, used to connect to the corresponding positive bus and negative bus in the DC bus;

[0012] The signal receiving port is provided with a wiring terminal for an externally connected insulating host, receiving a 485 signal sent by the insulating host and sending a daily heartbeat message;

[0013] A time relay, wherein the signal receiving terminal of the time relay is connected to the signal receiving port to realize external communication with the time relay;

[0014] The AC signal generator has an input end connected to the time relay and an output end connected to the signal receiving port, and is used as a signal source for AC intrusion by emitting a low-frequency AC signal.

[0015] Specifically, the signal receiving port is an RS485 signal receiving port.

[0016] Specifically, the power terminal is a two-star Phoenix terminal.

[0017] Specifically, the model of the time relay is CHINT time relay JSZ3A-A / DC24V.

[0018] Specifically, the model of the AC signal generator is JS-420ISG-V2-EN.

[0019] Specifically, the signal receiving port includes: a Phoenix terminal and an RS485 circuit;

[0020] Phoenix terminal is used to connect RS485 circuit;

[0021] The RS485 circuit is used to connect the signal receiving port and the time relay. The RS485 level signal received by the signal receiving port turns on the delayed closing function of the time relay.

[0022] The utility model device is set up on the DC bus, and receives the signal of the insulation host through the signal line, which defaults to the universal RS485 interface. The main function of the device is to open the time relay after receiving the signal when the insulation host is switched on and off daily, and to generate the AC intrusion signal generator for the DC bus within the response time, so as to simulate the fault alarm of the insulation host: inject low-frequency AC signal into the DC bus, and according to the minimum monitoring standard of AC intrusion, the insulation host needs to monitor the AC intrusion with a voltage level exceeding 10V. According to relevant standards, the voltage of the device is adjustable from 15 to 20V, which has little effect on the DC bus, but is sufficient for the insulation host to report the AC intrusion alarm, and then judge whether the insulation host is working normally during the daily inspection by the operation and maintenance team. This device is used to simulate the insulation monitoring accuracy of the insulation host that runs for a long time, which is of great significance. If there is no need to perform a timed simulation alarm of AC intrusion, the time relay of the device can be set to not trigger the device through the insulation host. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the utility model.

[0024] Figure 2 It is a schematic diagram of the circuit structure of the power terminal.

[0025] Figure 3 This is a schematic diagram of the circuit structure of the signal receiving port.

[0026] Figure 4 It is the circuit diagram of the AC signal generator.

[0027] Figure 5 This is the circuit diagram of the timing relay. DETAILED DESCRIPTION

[0028] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0029] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "vertical", "horizontal", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] Reference below Figure 1-5 Describe the utility model;

[0032] External AC inrush trigger device, including:

[0033] The power supply terminal, including the positive terminal and the negative terminal, is used to connect to the corresponding positive bus and negative bus in the DC bus to realize power supply to the device; the power supply voltage level of this device is DC110V~220V, which meets the DC bus voltage level of general substations.

[0034] The signal receiving port is provided with a wiring terminal for an externally connected insulating host, receiving a 485 signal sent by the insulating host and sending a daily heartbeat message;

[0035] The signal receiving port in this case is an RS485 signal receiving port, which is used to send the 485 signal sent by the external isolation host and the usual heartbeat message.

[0036] The time relay communicates with the signal receiving port, and the RS485 signal received by the signal receiving port is transmitted to the time relay, and then the time relay is energized under the set delay condition.

[0037] The AC signal generator has an input end connected to the time relay and an output end connected to the signal receiving port, and is used as a signal source for AC intrusion by emitting a low-frequency AC signal of 15 to 20V.

[0038] It is further defined that the model of the power terminal is a two-star Phoenix terminal.

[0039] It is further defined that the model of the time relay is JSZ3A-A / DC24V.

[0040] It is further specified that the model of the AC signal generator is JS-420ISG-V2-EN.

[0041] This case provides an external AC inrush trigger device, which is usually only connected to the DC bus and does not participate in any work. The RS485 signal port receives signals from the isolation host. Under normal circumstances, this device only sends heartbeat messages to the isolation host. Only after the isolation host starts the AC inrush monitoring step, this device participates in the work.

[0042] Here’s how this case works:

[0043] 1. Install the device on the DC bus and use the DC bus to supply power with a voltage of DC110V~220V;

[0044] 2. The signal receiving port is a universal RS485 port, which is connected to the insulated host through a signal line and usually sends heartbeat messages;

[0045] 3. When the insulation host is switched on and off every day, it sends a signal to this device, and by opening the internal time relay of this device, this device sends a low-frequency AC signal within the specified time;

[0046] 4. After the insulation monitoring host detects the low-frequency AC signal, it will eventually issue an AC inrush alarm;

[0047] 5. After the time is up, the time relay is disconnected, the low-frequency AC signal stops sending, and the alarm is naturally eliminated;

[0048] 6. On the second day, when the inspection team inspects the insulation host, if the detected AC inrush amplitude is 15-20V and the trigger time is the specified AC inrush historical alarm, the insulation monitoring accuracy and reliability of the insulation host can be determined;

[0049] If AC inrush actually occurs in the system, the inspectors can determine whether it is caused by factors such as the fixed trigger time of the device based on the time of occurrence, duration of occurrence, and amplitude of the AC inrush, thereby determining whether it is a true AC inrush and facilitating maintenance of the DC system.

[0050] Regarding the contents disclosed in this case, there are a few points that need to be explained:

[0051] (1) The drawings of the embodiments disclosed in this case only involve the structures involved in the embodiments disclosed in this case. Other structures can refer to the general design;

[0052] (2) In the absence of conflict, the embodiments and features of the embodiments disclosed in this case may be combined with each other to obtain new embodiments;

[0053] The above are only specific implementation methods disclosed in this case, but the protection scope of the present disclosure is not limited thereto. The protection scope disclosed in this case should be based on the protection scope of the claims.

Claims

1. External AC inrush trigger device, characterized in that: include: A power terminal, including a positive terminal and a negative terminal, used to connect to the corresponding positive bus and negative bus in the DC bus; The signal receiving port is provided with a wiring terminal for an externally connected insulating host, receiving a 485 signal sent by the insulating host and sending a daily heartbeat message; A time relay, wherein the signal receiving terminal of the time relay is connected to the signal receiving port to realize external communication with the time relay; The AC signal generator has an input end connected to the time relay and an output end connected to the signal receiving port, and is used as a signal source for AC intrusion by emitting a low-frequency AC signal.

2. The external AC intrusion trigger device according to claim 1, characterized in that: The signal receiving port is an RS485 signal receiving port.

3. The external AC intrusion trigger device according to claim 1, characterized in that: The power terminal is a two-star Phoenix terminal.

4. The external AC intrusion trigger device according to claim 1, characterized in that: The model of the time relay is JSZ3A-A / DC24V.

5. The external AC intrusion trigger device according to claim 1, characterized in that: The model of the AC signal generator is JS-420ISG-V2-EN.

6. The external AC intrusion trigger device according to claim 1, characterized in that: The signal receiving port includes: a Phoenix terminal and an RS485 circuit; Phoenix terminal is used to connect RS485 circuit; The RS485 circuit is used to connect the signal receiving port and the time relay. The RS485 level signal received by the signal receiving port turns on the delayed closing function of the time relay.

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