CN217789377U

CN217789377U - Fluid system protection device and gas turbine power generation system based on power source

Info

Publication number: CN217789377U
Application number: CN202122833898.9U
Authority: CN
Inventors: 王宇乐
Original assignee: Huaneng Shanghai Gas Turbine Power Generation Co Ltd
Current assignee: Huaneng Shanghai Gas Turbine Power Generation Co Ltd
Priority date: 2021-11-18
Filing date: 2021-11-18
Publication date: 2022-11-11
Anticipated expiration: 2031-11-18

Abstract

The utility model relates to a fluid system protection device and combustion engine power generation system based on power supply, wherein the device includes that at least two are mutual reserve power supply to and be used for switching over the interlocking controller of working power source when arbitrary power supply trouble, wherein, the power supply includes driving motor, power and control circuit, its characterized in that, the device still includes two sets (or a plurality of groups, the power supply quantity according to the concrete system configuration is decided) undercurrent relay, each undercurrent relay of group corresponds with each power supply one-to-one; and a current transformer is arranged on a power supply loop of a driving motor of the power source, the secondary side output of the current transformer is connected to a coil of an under-current relay in a corresponding control loop, and a normally open contact of the under-current relay is connected to the power supply input end of the corresponding power source. Compared with the prior art, the utility model has the advantages of reduce cost improves the protection effect.

Description

Fluid system protection device and combustion engine power generation system based on power source

Technical Field

The utility model belongs to the technical field of fluid protection and specifically relates to a fluid system protection device and gas turbine power generation system based on power supply is related to.

Background

In a fluid system using various pumps and fans as power sources, a method of setting a main pipe with low pressure and automatically starting a standby pump (fan) is generally adopted to ensure the reliability of working medium supply; meanwhile, in some occasions with automatic switching of the motor power supply bus power supply, when the bus voltage is lower than the limit value, all the running auxiliary machines on the bus are protected and stopped, and the protection of standby motors on other power supply buses is started, so that the phenomenon that the motor is burnt out due to overcurrent or the short interval time of switching of double power supplies of a fault power supply bus cannot be avoided due to long-time low voltage is avoided, and the overload of a bus power supply switch is caused.

However, the protection of the starting pump (fan) and the standby pump (fan) of the existing bus pipe pressure low-jump operation pump (fan) has quite high requirements on the reliability of a bus pipe pressure measurement value, and once a measurement loop fails or the protection logic is unreasonable, the standby pump (fan) is started by mistake, so that the overpressure of a system which is not provided with an overpressure protection device is caused.

In addition, in some application occasions, the low-pressure self-starting of the working medium main pipe is realized accurately, timely and reliably, and the requirement of bearing impact load of a system cannot be met. For example, in a system with an energy accumulator (or compressible fluid), once a working pump loses output due to shaft breakage and the like, due to the existence of the energy accumulator, the pressure of a main pipe slowly falls, and a protection action cannot be triggered at the first time, if the system needs large-capacity working medium supply at the moment, when the pressure of the main pipe of the system is low and the backup pump is started, the time for starting the backup pump (or a fan) by the optimal protection action is missed, and hidden danger is brought to safe operation of the system.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a fluid system protection device and combustion engine power generation system based on power supply exactly.

The purpose of the utility model can be realized through the following technical scheme:

a fluid system protection device based on a power source comprises at least two power sources which are mutually standby and an interlocking controller which is used for switching working power sources to work when any power source fails, wherein the power source comprises a driving motor, a power source and a control loop;

and a current transformer is arranged on a power supply loop of a driving motor of the power source, the secondary side output of the current transformer is connected to a coil of an under-current relay in the corresponding control loop, and a normally open contact of the under-current relay is connected to the power supply input end of the corresponding power source.

The driving motor is a three-phase input type driving motor, and each phase is provided with a current transformer.

The device also comprises two (or a plurality of) AND gate circuits, each AND gate circuit corresponds to all current transformers of each power source respectively, signals of each input end of each AND gate circuit are from secondary outputs of each phase current transformer of a driving motor of the corresponding power source, and the output end of each AND gate circuit is connected to the input end of an electric control loop of the corresponding power source.

The power source is a pump.

The power source is a fan.

And a comparator is also arranged between the current transformer and the AND gate circuit.

And a power supply input end of the power supply is provided with a current sensor, and an output signal of the current sensor is connected to a control loop of the corresponding power supply.

The under-current relay, the interlocking controller and the control loop are integrated in the same control cabinet.

A combustion engine power generation system comprises the device.

Compared with the prior art, the utility model discloses following beneficial effect has:

1. the low-voltage protection of the main pipe of the existing fluid system using a pump (fan) as a power source and the low-voltage protection of a power supply can be realized by adopting the undercurrent protection, the two protections are merged into one protection, the design principle of an electrical secondary loop is mature and simple, if the protection is realized by using thermal control logic, only a transmitter and a signal transmission line need to be added, the change amount of field equipment is small, and the actual implementation is easy.

2. If when the protection configuration is realized, if three-phase current series connection is adopted, namely, protection logic of an AND gate is adopted, compared with the existing protection configuration, the accuracy, the sensitivity and the reliability are all improved.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention;

wherein: 1. the system comprises a power source, 2, an interlocking controller, 3, a control loop and a power supply loop, K1, an under-current relay, K2 and an under-current relay.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

In a fluid system using various pumps and fans as power sources, under the condition of complete other protection configurations, the pressure of a main pipe is low and the voltage of a power supply is low, and the protection of the undercurrent of the pumps and the fans can be used for replacing simplification. In the application occasion of the centrifugal pump, by selecting proper action current, the undercurrent protection can also timely reflect the fault of cutoff of the inlet or the outlet of the running pump, and immediately act on tripping to avoid the damage of the pump body.

In order to ensure the reliability and accuracy of the under-current protection action, all three-phase currents can be introduced into the protection circuit, and when all the three-phase currents are smaller than a set value (by adopting AND gate logic), the related linkage action of the low-current protection is started.

The foregoing method may employ two approaches to achieve under-current protection.

1) The electric secondary circuit implementation method comprises the following steps: the control circuit of the pump (fan) driving motor is embedded with an under-current relay which is normally a normally open contact, after the pump (fan) is electrified and operated, a current transformer is electrified, the secondary side output current of the current transformer enables the contact of the under-current relay to be closed, when the current of the pump (fan) detected by the current relay is smaller than a set value, the contact of the relay is released, the pump (fan) is operated to trip, and a standby pump (fan) is started through an interlocking relation.

2) The thermal control logic implementation method comprises the following steps: the method comprises the steps of sampling all three-phase currents of a driving motor of a pump (fan) in real time, introducing numerical values into a thermal control module of the pump (fan) through a transmitter, adopting AND gate logic, triggering a logic outlet when all the sampled currents are smaller than a set value, tripping an operating pump (fan) through linkage action, and starting a standby pump (fan).

In the embodiment, an electric secondary circuit implementation method is adopted, and a fluid system protection device based on a power source can be applied to the fields of a gas turbine power generation system and the like, and comprises at least two mutually standby power sources 1 and an interlocking controller 2 for switching the power sources 1 to work when any one power source 1 fails, wherein the power source 1 comprises a driving motor and a control circuit, and the fluid system protection device is characterized by further comprising two under-current relays, and the two under-current relays are in one-to-one correspondence with the two power sources 1; and a control loop of a driving motor of the power source 1 is provided with a current transformer, the current transformer is connected to a coil of the corresponding under-current relay, and a normally open contact of the under-current relay is connected to a power input end of the corresponding power source 1. In fig. 1, K1 and K2 are undercurrent relays corresponding to the two power sources 1, respectively.

In this embodiment, the driving motor is a three-phase input type driving motor, and each phase is provided with a current transformer. Whether the pump or the fan is insufficient in output due to the abnormality of the body or the system, or the voltage of the power supply bus is reduced (or power is cut off), the current of the motor for driving the pump or the fan is abnormally reduced. Therefore, the under-current protection can be adopted to simultaneously protect the output reduction or power supply bus voltage abnormity of the pump and the fan caused by the body fault.

When the low current protection constant value is configured, an under current protection constant value which is slightly larger than the single motor of the driving motor and slightly smaller than the low value of the current fluctuation range when the pump (fan) normally runs is selected, so that the current of the driving motor of the pump or the fan falls into the protection constant value range when the pump or the fan is in the condition of shaft breakage, blade breakage or inlet and outlet cut-off and the like. The abnormal change of the current can be detected in real time by adopting related electrical measuring elements, and related protection actions can be triggered in time through corresponding thermal control or electrical protection loops and logic design, so that a failed running pump (fan) is stopped, further damage of the failed running pump (fan) is prevented, an interlocking controller is triggered, a standby pump (fan) is started immediately, and the reliability of working medium supply is ensured.

In some embodiments, the under-current protection may be implemented by using a thermal control logic block, inputs of the three current transformers are compared with a standard value, and when outputs of the three current transformers are all lower than a set value, the and gate circuit outputs a high level.

In this embodiment, a current transformer is provided at the power input end of the power source 1, and the current transformer is connected to the interlock controller 2, and the protection of low bus pressure is removed, so that the cost is lower, and the system reliability is higher.

In this embodiment, the undercurrent relay, the interlock controller 2 and the control loop are integrated in the same control cabinet, so that the structure is more compact.

By adopting the device, a circulating water system of the gas turbine power plant is protected, the circulating water system is a main pipe system, and three circulating pumps supply water to circulating water users of three units through a shared inlet and return water main pipe and are mainly used as cooling media of a condenser. Each unit is provided with two condenser water chambers respectively. Therefore, the minimum operation mode of the system is that one circulating pump carries two water chambers, and the maximum operation mode of three circulating pumps simultaneously supplies water to all six water chambers.

The system is not provided with an overpressure protection device, and once two water chambers with three or less water chambers or three water chambers with four or less water chambers are generated, the water supply amount of the circulating pumps far exceeds the water receiving amount of a user, so that the overpressure of the system is caused. Therefore, the system is not provided with the interlocking of the low-pressure self-starting standby circulating pump of the water inlet main pipe, so that the overpressure of the system caused by the false starting of the standby circulating pump is prevented.

According to the scheme, the current of the circulating pump in normal operation is about 190 amperes, and the current of the motor in idle load (without the pump) is about 85 amperes. When under-current protection is selected, the current protection constant value is selected to be 150 amperes; for a low speed running pump (energy saving modification), the current of the motor is about 60 amperes when the motor is unloaded, and the current of the motor is about 130 amperes when the motor is normally running, so that the fixed value of the current protection is selected to be 100 amperes.

Claims

1. A fluid system protection device based on a power source comprises at least two mutually standby power sources and an interlocking controller used for switching working power sources when any one power source fails, wherein the power source comprises a driving motor, a power circuit and a control circuit;

and a current transformer is arranged on a power supply loop of a driving motor of the power source, the secondary side output of the current transformer is connected to a coil of an under-current relay in a corresponding control loop, and a normally open contact of the under-current relay is connected to the power supply input end of the corresponding power source.

2. The power-source-based fluid system protection device of claim 1, wherein the drive motor is a three-phase input drive motor with a current transformer on each phase.

3. The protection device for fluid system based on power source of claim 2, further comprising two and gates, each and gate corresponding to all current transformers of each power source, wherein each input of the and gate is used for receiving signals from the secondary outputs of the current transformers of the driving motor of the corresponding power source, and the output is connected to the input of the electric control circuit of the corresponding power source.

4. The power-source-based fluid system protection device of claim 1, wherein the power source is a pump.

5. The power-based fluid system protection device of claim 1, wherein the power source is a fan.

6. The power-based fluid system protection device of claim 3, wherein a comparator is further provided between the output signal of the current transformer and the AND circuit when the protection is achieved by the thermal control logic.

7. The fluid system protection device based on a power source as claimed in claim 1, wherein the power source has a power input terminal provided with a current sensor, and the current sensor outputs a signal connected to the control circuit of the corresponding power source.

8. The power-source-based fluid system protection device of claim 1, wherein the undercurrent relay, the interlock controller and the control loop are integrated in the same control cabinet.

9. A combustion engine power generation system comprising an apparatus as claimed in any one of claims 1 to 8.