阅读说明：本技术 一种静止变频器冗余运行方法 (Redundancy operation method of static frequency converter ) 是由 张永会 鲍峰 李继凯 邵明航 洪波 姬联涛 李官军 于 2019-11-15 设计创作，主要内容包括：本发明提供了一种静止变频器冗余运行方法,包括第一SFC装置、SFC输入输出切换柜、SFC切换联锁、第二SFC装置,二次信号切换柜；输入切换柜、输出切换柜分为两套独立的开关柜,满足一主一备冗余运行模式和独立检修要求；第一SFC装置与第二SFC装置通过输入切换柜和输出切换柜进行输入输出隔离；第一SFC装置、第二SFC装置共用输入变压器TR1、输出变压器TR2、输入开关VCB11、输出开关VCB2系统外围设备。该SFC冗余运行方法拓扑简洁、闭锁完善、运行可靠、系统成本低。同时本方案可以有效提高同步电机启动成功率,降低维护运行费用,提高经济效益。本方法适用于新建抽蓄电站、调相机系统、燃气轮机领域冗余系统配置。(The invention provides a redundant operation method of a static frequency converter, which comprises a first SFC device, an SFC input/output switch cabinet, an SFC switch interlock, a second SFC device and a secondary signal switch cabinet; the input switching cabinet and the output switching cabinet are divided into two sets of independent switch cabinets, and the requirements of a main redundant operation mode, a standby redundant operation mode and independent maintenance are met; the first SFC device and the second SFC device are subjected to input and output isolation through an input switch cabinet and an output switch cabinet; the first SFC device and the second SFC device share input transformer TR1, output transformer TR2, input switch VCB11 and output switch VCB2 system peripheral equipment. The SFC redundancy operation method has the advantages of simple topology, perfect locking, reliable operation and low system cost. Meanwhile, the scheme can effectively improve the starting success rate of the synchronous motor, reduce the maintenance and operation cost and improve the economic benefit. The method is suitable for the configuration of redundant systems in the fields of newly-built extraction and storage power stations, phase modulator systems and gas turbines.)

1. A redundant operation method of a static frequency converter is characterized by comprising a first SFC device, an SFC input/output switch cabinet, an SFC switch interlock, a second SFC device and a secondary signal switch cabinet; the input switching cabinet and the output switching cabinet are divided into two sets of independent switch cabinets, and the requirements of a main redundant operation mode, a standby redundant operation mode and independent maintenance are met; the first SFC device and the second SFC device are subjected to input and output isolation through an input switch cabinet and an output switch cabinet; the first SFC device and the second SFC device share input transformer TR1, output transformer TR2, input switch VCB11 and output switch VCB2 system peripheral equipment.

2. The method of claim 1, wherein the first SFC device topology is identical to the second SFC device topology, and is a high-high topology or a high-low-high topology; the rectification inverter device adopts a 12-6 pulse type or a 6-6 pulse type.

3. The method of claim 1, wherein the SFC input/output switching device comprises an input switch cabinet and an output switch cabinet; in order to meet the requirements of a main redundant operation mode and an independent overhaul mode, QS4, QS3, QS5 and QS6 are a set of independent switch cabinets, and QS4b, QS3b, QS5b and QS6b are a set of independent switch cabinets.

4. The method of redundant operation of a stationary frequency converter according to claim 1, characterized in that said SFC switching interlock consists of a latch between input switches QS4, QS3, QS4b, QS3b, output switches QS5, QS6, QS5b, QS6b, ground switches QST, QSTb, system input switches VCB11, VCB12, system output switch VCB 2.

5. The method of claim 1, wherein the first SFC device performs independent maintenance and static debugging on the second SFC device during operation, and the second SFC device also performs independent maintenance and static debugging on the first SFC device during operation.

6. The method of claim 1, wherein only one set of external control signals of the SFC is required, and the control signals are switched to the corresponding SFC devices through the secondary signal switch cabinet according to the SFC device selected for operation.

7. The method of claim 1, wherein the first SFC device and the second SFC device are switched by local selection of the monitoring system or the switch cabinet.

Technical Field

The invention relates to the field of static frequency converters of large synchronous motor starting devices, and particularly provides a redundant operation method of a static frequency converter.

Background

The large synchronous motor is generally provided with two starting modes of frequency conversion starting and back-to-back starting, wherein the frequency conversion starting is mainly used generally, and the back-to-back starting is a standby starting mode. The variable frequency starting is that when the motor of the unit is started, alternating voltage with gradually increased frequency is added to a motor stator through a Static Frequency Converter (SFC) according to the position of the motor rotor or the voltage information of the motor end to generate a stator rotating magnetic field ahead of a rotor magnetic field, the motor rotor is accelerated to synchronous rotating speed through the interaction of the magnetic field and the rotor magnetic field, and then the unit is connected to the grid through a synchronous device. The static frequency converter has the advantages of stepless speed change, stable starting, high reaction speed, high regulation precision, strong self-diagnosis capability and the like.

At present, a Static Frequency Converter (SFC) is mainly used in the fields of pumped storage power stations, phase modifier systems and gas turbines. The pumped storage power station and the phase modulator system are generally only provided with one set of SFC to drag two to six synchronous motors, if the SFC equipment fails, the SFC equipment can only be dragged back to back through the synchronous motors, the utilization rate of the synchronous motors is reduced, the dragging time is long, and the adjusting precision is low.

Meanwhile, almost all SFC devices come from imports, mainly ABB, ALSTOM, Siemens and the like. Through investigation, it is found that the imported SFC device has problems in the aspects of after-sale service, spare parts and technical support, so that the problem of the equipment cannot be solved quickly, and the economic benefit is reduced.

Disclosure of Invention

The invention aims to provide a redundancy operation method of a static frequency converter, which aims to solve the following problems:

(1) under the condition of single SFC fault, the synchronous motor can not be started or can only be started back to back through another synchronous motor, so that the problem of low utilization rate of the synchronous motor is caused.

(2) The problems that the imported static frequency converter is not timely in after-sale service and technical support, the cost is high, the spare part purchasing time is long, the purchasing is difficult, the price is high and the like are solved.

(3) Under the condition of single SFC fault, the synchronous motor cannot be started quickly, and the economic benefit is lost.

In order to achieve the purpose, the invention adopts the following technical scheme:

a redundant operation method of a static frequency converter is characterized by comprising a first SFC device, an SFC input/output switch cabinet, an SFC switch interlock, a second SFC device and a secondary signal switch cabinet; the input switching cabinet and the output switching cabinet are divided into two sets of independent switch cabinets, and the requirements of a main redundant operation mode, a standby redundant operation mode and independent maintenance are met; the first SFC device and the second SFC device are subjected to input and output isolation through an input switch cabinet and an output switch cabinet; the first SFC device and the second SFC device share input transformer TR1, output transformer TR2, input switch VCB11 and output switch VCB2 system peripheral equipment;

the first SFC device topological structure is consistent with the second SFC device topological structure, and can be a high-high topology or a high-low high topology.

The SFC input/output switching device consists of an input switching cabinet and an output switching cabinet, wherein a switching switch can be an isolating switch, a breaker, a contactor and a load switch, and the switching switch is usually switched without load or electricity. The structure form can be a drawing type or a fixed type, and can be operated manually or electrically.

The SFC switching interlocking scheme is composed of input switching switches QS4, QS3, QS4b and QS3b, output switching switches QS5, QS6, QS5b and QS6b, grounding switches QST and QSTb, system input switches VCB11 and VCB12 and a system output switch VCB 2.

The first SFC device can be independently overhauled and statically debugged when running, and the second SFC device can also be independently overhauled and statically debugged when running.

The external control signals (synchronization, monitoring, excitation and the like) of the SFC only need one set, and the control signals are switched to the corresponding SFC devices through the secondary signal cabinet according to the selected running SFC devices.

The first SFC device and the second SFC device can be switched by local selection of a monitoring system or a secondary signal switch cabinet.

The invention has the advantages that: by the aid of the method, the synchronous motor static frequency converter redundancy operation design is realized, independent operation of the SFC device in a primary-secondary redundancy mode is realized, the utilization rate and economic benefit of the synchronous motor are improved, and the reliability and stability of the device are improved. Meanwhile, when the existing SFC devices in the field of extraction and storage power stations, phase modulation systems and gas turbines are subjected to redundancy transformation, the first SFC device or the second SFC device can be a domestic device, the response time of after-sale and technical service is fast, spare parts are convenient to purchase, the period is short, and the price is low.

The invention will be further explained with reference to the drawings.

Drawings

FIG. 1 is a circuit diagram of the present invention.

Fig. 2 is a schematic diagram of a secondary signal switching circuit of the present invention.

Detailed Description

Referring to fig. 1 and 2, a method for redundant operation of a static frequency converter includes a first SFC device, an SFC input/output switch cabinet, an SFC switch interlock, a second SFC device, and a secondary signal switch cabinet; the input switching cabinet and the output switching cabinet are divided into two sets of independent switch cabinets, and the requirements of a main redundant operation mode, a standby redundant operation mode and independent maintenance are met; the first SFC device and the second SFC device are subjected to input and output isolation through an input switch cabinet and an output switch cabinet; the first SFC device and the second SFC device share input transformer TR1, output transformer TR2, input switch VCB11 and output switch VCB2 system peripheral equipment.

Referring to fig. 1, the SFC device 12-6 pulse height architecture is shown. The system diagram is for a conventional device, but is not limited to 12-6 pulse type, and may be 6-6 pulse type or other types. The two sets of SFC devices share system peripheral equipment such as an input transformer TR1, an output transformer TR2, an input switch VCB11, an output switch VCB2 and the like.

As shown in fig. 1, the first SFC device (SFC 1) and the second SFC device (SFC 2) include a rectifier cabinet, a reactor cabinet, and an inverter cabinet (inverter cabinet). The rectifier cabinet is composed of a rectifier device taking silicon controlled rectifier as a core, an auxiliary cooling device and other accessories. Thyristors are generally power electronic devices such as thyristors. The reactor cabinet consists of a smoothing reactor, an auxiliary cooling device and other accessories. The inverter cabinet consists of a rectifying device taking silicon controlled rectifier as a core, an auxiliary cooling device and other accessories. The cooling device can be forced air cooling heat dissipation cooling or forced water cooling heat dissipation cooling. Usually, in order to ensure reliable triggering of the thyristor, the rectifying and inverting device supplies power to the triggering circuit by adopting a self-power-taking mode from a buffer circuit of the thyristor. Meanwhile, in order to ensure that the inverter is reliably triggered at a low-frequency stage, the inverter supplies power to the trigger circuit in a CT self-energy-taking mode.

As shown in fig. 1, the first SFC device is input-output isolated from the second SFC device by the input switch cabinet and the output switch cabinet. In the input switch cabinet and the output switch cabinet, the switches can be isolating switches, circuit breakers, contactors and load switches, and the switches are usually switched without load or electricity. The structure form can be a drawing type or a fixed type, and can be operated manually or electrically. And necessary accessories such as PT, CT, a charged display and the like for corresponding protection are arranged in the switch cabinet. In order to ensure that the first SFC device and the second SFC device realize a main-standby redundant operation mode and independent maintenance requirements, the input switch cabinet and the output switch cabinet are divided into two sets of independent switch cabinets, namely QS4, QS3, QS5 and QS6 are a set of independent switch cabinets, and QS4b, QS3b, QS5b and QS6b are a set of independent switch cabinets. Therefore, the first SFC device can be independently overhauled and statically debugged when running, and the second SFC device can also be independently overhauled and statically debugged when running.

As shown in fig. 1, the primary-to-primary redundancy operation primary switching logic of the first SFC device and the second SFC device is as follows:

the newly added switch QS3, QS4, QS3b, QS4b, QS5, QS6, QS5b and QS6b are provided with electric operating mechanisms, and automatic switching can be realized through a key-provided selection switch in the secondary signal switch cabinet. Through the control of the newly added change-over switch, the switching of the rectification inversion unit and the smoothing reactor in the two sets of SFC primary circuits is realized, and the states of the main circuit change-over switch control and the like are displayed.

When the selection switch is in the position of 'SFC 1', QS3/QS4/QS5/QS6 are disconnected, QS3b/QS4b/QS5b/QS6b are closed, and external related signals are switched to an SFC1 variable-frequency starting system, so that the unit is controlled by starting of the SFC 1; when the selection switch is in: when the position of the SFC2 is 'SFC 2', QS3/QS4/QS5/QS6 are closed, QS3b/QS4b/QS5b/QS6b are opened, and external related signals are switched to an SFC2 frequency conversion starting system, so that the starting control of the unit by the SFC2 is realized.

In order to ensure independent live operation, the change-over switch and the system input/output switch need to be locked reliably. The locking scheme is as follows:

the switching switches QS3, QS4, QS3b, QS4b, QS5, QS6, QS5b and QS6b are locked with the system input and output switches VCB11 and VCB2, and when VCB11 and VCB2 are switched on, QS3, QS4, QS3b, QS4b, QS5, QS6, QS5b and QS6b cannot be operated; QS3, QS4, QS3b, QS4b, QS5, QS6, QS5b, QS6b may be operated when VCBs 11, 2 are gated off. QS3, QS4, QS5 and QS6 are interlocked with QS3b, QS4b, QS5b and QS6b, QS3b, QS4b, QS5b and QS6b can only operate when QS3, QS4, QS5 and QS6 are switched off, and QS3, QS4, QS5 and QS6 can only operate when QS3b, QS4b, QS5b and QS6b are switched off; QS3, QS4, QS5 and QS6 are switched on, QS3b, QS4b, QS5b and QS6b are not operated, and QS3b, QS4b, QS5b and QS6b are switched on, QS3, QS4, QS5 and QS6 are not operated.

When the SFC1 or the SFC2 inputs the switch cabinet grounding switch and outputs the grounding switch to be grounded, the corresponding QS3, QS4, QS5, QS6 or QS3b, QS4b, QS5b and QS6b cannot be switched on; the corresponding input switching cabinet and output switching cabinet doors can be opened.

As shown in fig. 2, the external control signals are switched by the secondary signal switch cabinet, so that only one set of SFC external control signals (synchronization, monitoring, excitation, etc.) is needed, and when the corresponding selection switch selects the SFC1 or the SFC2 device to operate, the secondary signal switch cabinet switches the control signals to the corresponding SFC device. The switching logic is as follows:

the secondary signal switch cabinet divides the external signals into two paths, one path is connected to SFC1 equipment, the other path is connected to SFC2 equipment, and the two paths of signals are not interfered with each other. The switching of the corresponding signals of the two sets of equipment is realized by a control relay. K1, K2 are switching relays, when the coils of K1, K2 are in a demagnetized state, an external signal is input to an SFC1 system through a normally closed node of the switching relay K1, and an output signal of the system is sent to the outside through K2 similarly; when the coils of the K1 and the K2 are in an excitation state, the normally open node is closed, the normally closed node is opened, an external signal is sent to the SFC2 system, and an output signal of the system is sent to the outside. The switching relay control is interlocked with the position and the mechanical position of the primary switch and the system input/output circuit breaker, and the position signal is accessed into each SFC system to be used as a switching logic judgment condition. Therefore, signals related to the SFC system and the outside are switched by the secondary signal switching cabinet, and the signal sharing of one set of external signals and the signals of two sets of equipment is realized.