Starting system of diesel generating set

Abstract

The utility model provides a starting system of a diesel generating set. The starting system comprises a DCS (Distributed Control System) controller, a diesel generator controller and three voltage relays, in A, B and C three-phase lines of the security section bus, a voltage relay is connected between two phases respectively; the three voltage relays are respectively connected to the input end of the DCS controller, and the output end of the DCS controller is connected to the input end of the diesel generator controller. According to the utility model, low-voltage action signals of the three single-phase voltage relays are connected into the DCS controller, and after the low-voltage action signals are judged by two-out-of-three logic designed in the DCS controller, bus under-voltage signals are sent into the diesel generator controller, so that the reliability and the safety of the security power supply are improved, and the safety of the diesel generator is improved. And potential safety hazards caused by wiring looseness, fuse damage or relay damage are avoided. And the undervoltage signal is introduced into the DCS controller, so that an affair recall function is added, and reason investigation and analysis in an accident state are facilitated.

Description

TECHNICAL FIELD

[0001] The utility model relates to electrical engineering or electric power system field, concretely relates to a diesel generating set starting system. BACKGROUND

[0002] 400V accident security section bus is a bus in the power system specially used for accident security, and its voltage grade is 400V, the main function of the bus is to provide standby power supply for key equipment or system when power accident occurs, to ensure that it can continue to run or safely shut down. It is usually connected to a diesel generator or other emergency power supply to provide power support after the main power supply is lost. Taking the 400V accident security section bus of the coal-fired unit as an example, its configuration usually includes: one working power supply, one standby power supply and one diesel generating set emergency power supply. Under normal circumstances, the working power supply drives the load, when the working power supply fails, the standby power supply is switched on, and when the standby power supply also loses power, the diesel generating set is started to drive the load through power generation.

[0003] The voltage monitoring circuit is a circuit used for monitoring voltage changes in the power system, which is usually composed of voltage transformers, voltage relays, time relays and other elements. The voltage monitoring circuit can monitor the voltage changes of the power system in real time, and when the voltage is abnormal (such as voltage reduction or disconnection), it can send out an alarm signal in time and take appropriate protective measures to prevent equipment damage or accidents. The voltage monitoring circuit is usually configured at the inlet and outlet of key parts of the power system, such as bus, transformer, generator and other equipment, which is connected to the voltage transformer to monitor voltage changes in real time and send out alarm signals through voltage relays and other elements.

[0004] At present, the method for monitoring the 400V accident security section bus by the voltage monitoring circuit is: a three-phase relay is connected to the 400V accident security section bus to monitor the loss of voltage of the 400V accident security section bus, and when any phase of the bus three-phase loses voltage, an alarm signal is sent out to start the diesel generating set. However, due to loose wiring, damaged relays, damaged secondary insurance and other reasons, the bus will lose voltage for a short time, and the voltage detection module will output an under-voltage signal, resulting in false start of the diesel generating set, causing hidden danger of diesel generator start, and affecting the safe operation of the main machine. UTILITY MODEL CONTENTS

[0005] The utility model aims at solving the defects existing in the prior art, and provides a diesel generating set starting system.

[0006] The utility model provides a diesel generating set starting system, which comprises a DCS controller and a diesel generator controller, and further comprises three voltage relays.

[0007] In the A, B, C three-phase lines of the security section bus, two phases are connected with one of the voltage relays respectively;

[0008] The three voltage relays are connected to the input end of the DCS controller respectively, and the output end of the DCS controller is connected to the input end of the diesel generator controller.

[0009] According to the diesel generator set starting system, the A, B, C three-phase lines of the security section bus are connected with corresponding voltage relays, and the fuses are connected between the three-phase lines and the voltage relays.

[0010] According to the diesel generator set starting system, the action voltage value of the three voltage relays is 65-80% of the rated voltage.

[0011] According to the diesel generator set starting system, the delay contact of the DCS controller is delayed for 3s.

[0012] According to the diesel generator set starting system, the diesel generator controller is a DSE-701 diesel generator controller.

[0013] According to the diesel generator set starting system, the DCS controller is a SIMOTION controller.

[0014] According to the diesel generator set starting system, the security section bus is a 400V accident security section bus.

[0015] According to the diesel generator set starting system, the voltage relay is a CM-ESS.MS single-phase relay.

[0016] According to the diesel generator set starting system, the three voltage relays are arranged at the lower opening of the secondary fuse of the security section bus.

[0017] Beneficial effects:

[0018] The diesel generator set starting system has the advantages that the low voltage action signals of the three single-phase voltage relays are connected to the DCS controller, the three-two logic in the DCS controller is used for judgment, the DCS sends the bus under-voltage signal to the diesel generator controller when the judgment result of two or three single-phase voltage relays is the low voltage action signal, and the diesel generator is started, so that the reliability and safety of the security power supply are improved, the diesel generator is prevented from being started by mistake due to loose wiring, damaged fuse or damaged relay, the under-voltage signal is introduced into the DCS controller, the fault memory function is increased, and the cause investigation and analysis under the accident state are facilitated. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The diesel generator set starting system provided by the utility model;

[0020] Figure 2 This is a schematic diagram of the connection between the voltage relay and the safety section bus;

[0021] Figure 3 This is a schematic diagram of the connection between three voltage relays and the DCS controller;

[0022] Reference numerals:

[0023] 11-A phase voltage relay; 12-B phase voltage relay; 13-C phase voltage relay; 2-DCS controller; 3-diesel generator controller; 4-fuse. DETAILED DESCRIPTION

[0024] To make the purpose, technical solutions, and advantages of the present invention more clear, the following provides a clear and complete description of the technical solutions of the present invention. Obviously, the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0025] Coal-fired units, as crucial components of the power system, are responsible for converting the chemical energy of coal into electrical energy. The 400V emergency busbar is a crucial power distribution node within the unit, providing power to critical equipment and auxiliary machinery under normal circumstances. When a coal-fired unit's main power source fails or requires maintenance, the 400V emergency busbar becomes a crucial backup power source, ensuring the unit can maintain essential operations in an emergency and preventing further damage from the incident.

[0026] The configuration of the 400V emergency bus usually includes multiple incoming power sources, including 1 working power source, 1 backup power source, and 1 diesel generator set power source. The working power source and the backup power source are connected from different plant low-voltage power centers, while the diesel generator set power source is used for automatic and rapid starting to ensure that power can be quickly provided when the main power fails. When the emergency bus loses power, the system will issue an audible and visual alarm, such as "400V emergency bus low voltage drop" and "400V emergency bus incoming line switch tripping", prompting the operator to handle it. The system will use the working / backup power source incoming line circuit breaker and the diesel generator set feeder circuit breaker to interlock each other, realizing the switching of the power source. If the backup power source is successfully closed, the diesel generator set will stop running; if the working power source is tripped and the backup power source fails to close, the diesel generator set will automatically start and gradually load until full load.

[0027] The diesel generator set is a power supply equipment with a diesel engine as the original motor, dragging a synchronous generator to generate electricity. It is a start-up fast, easy to operate and maintain, low investment, and strong environmental adaptability power generation device. The diesel generator set is a power generation equipment mainly using diesel as fuel, using a diesel engine as the original power to drive a synchronous generator to generate electricity, converting kinetic energy into electrical and thermal energy. The diesel generator set is usually configured as a backup power source for coal-fired units. When the main power source (such as grid power supply or the power generation system of the coal-fired unit itself) fails and the 400V emergency bus loses power, the diesel generator set can quickly start and connect to the 400V emergency bus to provide power for critical equipment and auxiliary machines, ensuring that these devices can continue to operate in emergency situations.

[0028] The diesel generator set and the 400V emergency bus usually have an automatic switching device and a linkage control logic. When detecting voltage abnormalities or power loss of the 400V emergency bus, the automatic switching device will quickly start the diesel generator set and connect its output power to the 400V emergency bus through the linkage control logic, realizing seamless switching. This automatic switching and linkage control ensures the continuity and reliability of power supply.

[0029] During the operation of the coal-fired unit, various unexpected situations may occur, such as bus failure, short circuit, etc., which may cause voltage abnormalities. The voltage monitoring circuit of the 400V emergency bus can monitor the voltage state in real time and issue an alarm when the voltage is abnormal, reminding the operator to take timely measures. However, when the voltage monitoring circuit is loose due to any phase connection, the voltage detection module will output an under-voltage signal, which will mistakenly start the diesel generator set. In order to avoid this problem, the utility model provides a diesel generator set starting system, Figure 1 The diesel generator set starting system provided by the utility model, likeFigure 1 The system comprises a DCS controller 2, a diesel generator controller 3, and further comprises three voltage relays; two voltage relays are connected between each of the A, B and C phase lines of the security section bus; the three voltage relays are connected to the input end of the DCS controller 2 respectively, and the output end of the DCS controller 2 is connected to the input end of the diesel generator controller 3.

[0030] Specifically, Figure 2 The connection diagram of the voltage relays and the security section bus is shown in the figure, Figure 2 The three voltage relays are an A-phase voltage relay 11, a B-phase voltage relay 12 and a C-phase voltage relay 13 respectively; the A-phase voltage relay 11 is connected between the A phase and the B phase of the security section bus; the B-phase voltage relay 12 is connected between the B phase and the C phase of the security section bus, and the C-phase voltage relay 13 is connected between the A phase and the C phase of the security section bus. The DCS controller 2 is used for making a two-out-of-three judgment on the input signals and sending the judgment result to the diesel generator controller 3, and the diesel generator controller 3 is connected to the diesel generator through a wire to control the diesel generator to start.

[0031] The utility model discloses a single three-phase relay of the integrated structure design of the prior art is used for monitoring three-phase voltage, changes to use three CM-ESS.MS single-phase relays to monitor security section bus three-phase voltage respectively, then the low voltage action signal of three single-phase relays is connected to the DCS controller, judges by the two-out-of-three logic designed in the DCS controller, and then sends the bus under-voltage signal to the diesel generator controller. The starting method of the diesel generator set is as follows:

[0032] Step one, three low voltage relays are added under the secondary fuse of the security section bus to monitor the three-phase voltage of the security section bus respectively;

[0033] Step two, the under-voltage action signals of the three low voltage relays are introduced into the DCS to make a two-out-of-three judgment, and the security section bus under-voltage signal is judged through the DCS logic;

[0034] Step three, finally, the DCS controller sends the bus under-voltage starting instruction to the diesel generator controller to start the diesel generator.

[0035] The diesel generating set starting system provided by the utility model, through connecting the low voltage action signal of three single-phase voltage relays to the DCS controller, judging by the two-out-of-three logic designed in the DCS controller, after judging the result of low voltage action signal of two or three of the three single-phase voltage relays, the DCS sends the bus under-voltage signal to the diesel generator controller, thereby starting the diesel generator. Thus, the reliability and safety of the security power supply are improved, and the mis-starting of the diesel generator caused by loose wiring, fuse damage or relay damage is avoided. Moreover, by introducing the under-voltage signal into the DCS controller, the fault memory function is increased, and the cause investigation and analysis under the fault state are facilitated.

[0036] Further, as shown in the figure, between the A, B, C three-phase lines of the security section bus and the corresponding voltage relays, there are fuses 4. Figure 2

[0037] Specifically, the function of the fuse is to detect the overcurrent in the circuit. When the current in the circuit exceeds the rated current of the fuse, the protection element in the fuse will melt, thereby cutting off the circuit and preventing overcurrent from causing damage to the circuit and equipment. In addition to overcurrent, the fuse can also provide protection when a short circuit occurs in the circuit. The utility model connects the fuse between the security section bus and the voltage relay, which can ensure the safe operation of the circuit and equipment; and by melting the fault circuit in time, the fuse can protect the equipment, prevent fire, improve system reliability and simplify maintenance work.

[0038] Further, the action voltage value of the A-phase voltage relay 11, the B-phase voltage relay 12 and the C-phase voltage relay 13 is 65-80% of the rated voltage.

[0039] By setting the action voltage value of the voltage relay to 65-80% of the rated voltage, the circuit system of the diesel generating set starting system can be quickly responded.

[0040] Further, the delay contact of the DCS controller is delayed for 3s.

[0041] Specifically, in some cases, due to signal interference or fluctuation, the relay may frequently act in a short time, causing the system to be unstable. The delay setting can effectively reduce the misoperation caused by signal fluctuation, making the system more stable.

[0042] Further, the diesel generator controller is a DSE-701 diesel generator controller; the DCS controller is a SIMOTION controller; the security section bus is a 400V fault security section bus. The voltage relay is a CM-ESS.MS single-phase relay.

[0043] ​It should be finally pointed out that: the above examples are only used to illustrate the technical solutions of the utility model, and not to limit them; although the utility model has been explained in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement to part 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 utility model.

Claims

1. A diesel generator starting system, comprising: The DCS controller (2) and the diesel generator controller (3) are characterized by further comprising: three voltage relays; In the three-phase lines A, B, and C of the security section bus, one voltage relay is connected between each of the two phases; The three voltage relays are respectively connected to the input end of the DCS controller (2), and the output end of the DCS controller (2) is connected to the input end of the diesel generator controller (3).

2. The diesel generator starting system according to claim 1, characterized in that: Fuses (4) are connected between the A, B, and C three-phase lines of the safety section busbar and the corresponding voltage relays.

3. The diesel generator starting system according to claim 1, characterized in that: The operating voltage values ​​of the three voltage relays are 65-80% of the rated voltage.

4. The diesel generator starting system according to claim 1, characterized in that: The delay contact of the DCS controller (2) is delayed by 3 seconds.

5. The diesel generator starting system according to claim 1, characterized in that: The diesel generator controller (3) is a DSE-701 diesel generator controller.

6. The diesel generator starting system according to claim 1, characterized in that: The DCS controller is a SIMOTION controller.

7. The diesel generator starting system according to claim 1, characterized in that: The safety section bus is a 400V accident safety section bus.

8. The diesel generator starting system according to claim 1, characterized in that: The voltage relay is a CM-ESS.MS type single-phase relay.

9. The diesel generator starting system according to claim 1, characterized in that: The three voltage relays are all arranged at the lower port of the secondary fuse of the safety section bus.

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