KR101029301B1 - Digital control system for controlling voltage of synchronous generator - Google Patents

Abstract

In order to compensate for the lack of computing power of general general PLC digital controllers, a digital control system for synchronous generator voltage control consisting of triplexed SCBs is provided.

A digital control system for synchronous generator voltage control includes: a digital controller for performing a main control operation for controlling an output voltage and reactive power of a generator; A signal processing system for measuring the voltage, power, field voltage, field current, frequency, and phase of the generator and converting the signal into a standard signal suitable for the digital controller and transmitting the same to the digital controller; A thyristor phase control rectifier for converting AC power into DC power according to the magnitude of the signal of the digital controller; A generator voltage / current transformer for detecting the voltage and current of the generator; A field voltage / current detector for detecting signals of voltage and current of the field circuit; And an MMI system that monitors operation data and performs system operations.

According to the digital control system for synchronous generator voltage control according to the present invention it is possible to replace the expensive dedicated generator voltage controller with a general-purpose PLC-class digital controller.

PLC, SCB, Digital Controller, Thyristor Phase Control Rectifier, Voltage / Current Transformer

Description

DIGITAL CONTROL SYSTEM FOR CONTROLLING VOLTAGE OF SYNCHRONOUS GENERATOR}

The present invention relates to a construction strategy of a generator control system. The present invention relates to a technical field for effectively controlling generator voltage by connecting a general-purpose controller and a self-developed signal processing system, and more particularly, to a digital control system for synchronous generator voltage control.

The generator voltage controller receives a fault signal for closed-loop control from a voltage transformer (PT) and a current transformer (CT) located at the generator output stage. Since this signal is an AC signal of 60Hz, it must be converted into a standardized DC signal required by a general industrial digital controller. Simple conversion of the magnitude of the AC signal to the magnitude of the DC signal is possible through a simple rectifier.

However, the generator voltage controller needs not only the generator output voltage but also the generator active power, reactive power, frequency, etc. as essential signals.These signals cannot be generated by simple rectifier circuits, but are complex integrated circuits (ICs). You must use hardware and computing software with

Conventionally, signal processing was performed using a high speed digital control system of 10 msec or less dedicated for generator control systems. However, such a dedicated generator voltage controller has a disadvantage that it is not possible to use universally and expensive as it is dedicated for controlling the generator voltage.

Therefore, in view of these shortcomings, the conventional general programmable logic controller (PLC) class digital controller can be considered as a controller of the digital excitation system. However, this requires high-speed data collection and processing.

However, PLC-class digital controllers have a problem in that it is difficult to handle 1800 Hz, which is the signal processing PT and CT sampling time for controlling the excitation system due to the limitation of the processing speed (usually 10-100 Hz).

Therefore, the present invention was devised in view of the above problems, and an object of the present invention is to process a signal at a high speed of 1 msec or less at a frequency of 1800 Hz or more in a separate digital signal processing printed circuit board for generator voltage control signal processing, and to standardize a direct current. It converts the signal (0 ~ 10VDC, 4 ~ 20mADC) and sends it to the triple digital digital programmable logic controller which has a calculation time of about 20msec which is generally used for industrial process control.The generator automatic voltage control, automatic reactive power control, automatic In addition to performing control operations such as power factor control, as well as transformers connected to the main body of the synchronous generator, the generator output stage, and limiting and protection-related logic for protecting the excitation system safely from electrical or thermal disturbances, digital for synchronous generator voltage control To provide a control system.

According to an aspect of the present invention, there is provided a digital control system for synchronous generator voltage control, the digital control system for synchronous generator voltage control comprising: a digital controller for performing a main control operation for controlling the output voltage and reactive power of the generator; A signal processing system that measures the voltage, power, field voltage, field current, frequency, and phase of the generator, converts the signal into a standard signal suitable for the digital controller, and transmits the signal to the digital controller; A thyristor phase control rectifier for converting AC power into DC power according to the magnitude of the signal of the digital controller; A generator voltage / current transformer for detecting the voltage and current of the generator; A field voltage / current detector for detecting signals of voltage and current of the field circuit; And an MMI system that monitors operation data and performs system operations.

The digital controller and the signal processing system may be tripled.

The digital controller may be a general-purpose PLC controller.

The digital controller may receive signals from the triplex signal processing system and select intermediate values thereof as standard signals.

When a problem occurs in any one of the triplexed signal processing system, any one signal processing system having the problem transmits a fault signal to the triplex digital controller, and the triplex digital controller generates a fault signal in response. The signal of the signal processing system is excluded and a maximum or minimum value of two signals from another signal processing system is selected and the standard signal is selected. The fault signal is again generated in one of the two signal processing systems. If so, the signal processing system that generated the Fault signal can be excluded again and the entire control can be performed with the remaining signal processing system.

The generator control system first converts the alternating voltage signal of the generator voltage and current into a digital signal, filters the noise, and vectorizes the current and the voltage to calculate active / reactive power and frequency signals. Since this process requires very fast computational speed, it takes up a lot of memory capacity and has a lot of computational load. As a result, the operation speed of the triple controller was significantly reduced, which prevented the effective control of generator terminal voltage and reactive power, which are the main tasks of the generator control system. Accordingly, the digital control system for synchronous generator voltage control according to the present invention is equipped with a separate signal processing system in a universal controller to give about 50% of such a general-purpose controller calculation capacity to use a universal controller without a dedicated controller for synchronous generator voltage control. To be effectively controllable.

In addition, in the case of the dedicated controller, due to the limitation of the internal program software of the dedicated controller, there are limitations in terms of flexibility, such as system fault diagnosis, compared to the general-purpose controller having various functional blocks. Can be effectively overcome.

Hereinafter, the same reference numerals will be described in detail with reference to the accompanying drawings, with reference to the same components preferred embodiments of the present invention. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and should be construed in accordance with the technical meanings and concepts of the present invention.

The embodiments described in the specification and the configuration shown in the drawings are preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, various equivalents and modifications that can be substituted for them at the time of the present application are There may be.

1 is a block diagram showing a digital control system for synchronous generator voltage control according to an embodiment of the present invention.

Referring to FIG. 1, the digital control system 1 for synchronizing generator voltage control according to an embodiment of the present invention includes a digital controller 10, a signal processing system 20 (hereinafter referred to as SCB), a thyristor phase control rectifier. (30), generator voltage transformer (PT) and current transformer (CT), field voltage detector (DC PT) and field current detector (Hall CT), and MMI (Man Machine Interface) system 40 It consists of.

The digital controller 10 is tripled to increase the reliability of the system and performs a main control operation function for controlling the output voltage and reactive power of the generator.

The SCB 20 measures the generator voltage, power, field voltage, field current, frequency, phase, etc. to improve the operation speed of the controller, converts them into standard signals suitable for the controller, and transmits them to the digital controller 10. Performs the function of executing the system stabilizer (PSS) algorithm. The SCB 20 is also tripled to improve system reliability like the triple digital controller.

The thyristor phase control rectifier 30 converts AC power into DC power according to the magnitude of the signal of the digital controller 10.

The generator voltage / current transformers PT and CT serve to detect the voltage and current of the generator.

The field voltage / current detectors DC PT and Hall CT detect signals of voltage and current of the field circuit, and the MMI system 40 plays a role for monitoring operation data and operating a system.

Hereinafter, the digital control system for synchronizing generator voltage control according to an embodiment of the present invention will be described in more detail with reference to FIGS. 2 to 9.

FIG. 2 is a block diagram illustrating a connection configuration of the voltage / current transformers PT and CT, the SCB 20, and the digital controller 10 included in the synchronous generator voltage control digital control system of FIG. 1.

Referring to FIG. 2, the signals of the generator voltage and current are input to the SCB 20 which is tripled, and the input signals are converted into a signal suitable for the digital controller 10 and then calculated and input to the triplex controller.

The SCB 20 transmits signals to each of the triplexed digital controllers 10, and the digital controller 10 which receives the signals can select an intermediate value thereof as a standard signal.

In addition, the SCB 20 may include a self-diagnostic function. For example, when one of the tripled SCBs 20 fails or a problem occurs in the power supply, a fault signal is sent to the tripled digital controller 10. The triple digital controller 10 excludes the signal from which the Fault signal is generated, selects the maximum / minimum (user selection) value among the values of the other two signals, and selects it as a standard signal to operate.

If a Fault signal is generated again in one SCB 20 out of the two signals, the SCB 20 in which the Fault signal is generated is excluded again and total control is performed with the last remaining sound SCB 20. At this time, if the last one again generates a fault signal, the triple digital controller 10 stops the entire system as a whole system stop.

FIG. 3 is a block diagram illustrating the internal circuit of the digital controller shown in FIG. 2 in more detail, and illustrates a flow in which an output signal calculated by the controller is output as a firing signal of a rectifier.

3 also shows the input / output module structure of the general-purpose digital controller 10 and the communication structure of the main calculator.

Referring to FIG. 3, the main control processors (Main Processors A, B, and C) inside the digital controller 10 share the calculation result with data input through the internal Tri Bus, and three separate outputs of the output module. The values are selected as final output values through the voter circuit.

The final output values selected by the digital controller 10 are inputted to the phase control rectifiers A, B, C, and D. In accordance with the signal of the digital controller 10, the AC power is converted into DC power in the rectifier and finally the voltage of the synchronous generator and The reactive power control is performed.

4 is a block diagram of a main control program stored in the digital controller shown in FIG. 2, and illustrates a flow of receiving an input signal calculated by the SCB 20 and outputting a final output, that is, a signal for rectifying the rectifier. The main program contents include over- flux limiting, automatic / manual voltage setting and control, under-excitation current limiting, reactive cross flow compensation, voltage transformer fault detection, automatic / manual selection, and over-excitation limiting.

In Fig. 4, for each functional block, V / Hz: confectionery limiter, AVR Ramp Block: automatic voltage setter, PSS: power system stabilizer, UEL: underexcitence limiter, RCC: reactive crossflow compensator, MVR Ramp Block: Manual voltage setter, PI: Proportional integral controller, PT Fail Detect: Voltage transformer fault detection, AUTO / MAN MODE SEL: Mode selection, MIN SEL: Minimum value selector, 52G Closed: Generator system I / O circuit breaker, OFFLINE_REF : Set value before line feed and ONLINE_REF: set value after line feed.

FIG. 5 shows an internal hardware signal connection diagram of the SCB shown in FIG. 2. Referring to FIG. 5, the signals input to P1 are input to a digital signal processing unit (hereinafter referred to as DSP) through an input unit such as a generator three-phase voltage using an LEM sensor, an A / D converter of an analog signal, and a DSP. After operation, the data is stored in various memory devices (EPROM, FLASH MEM., SREM), and then outputted through an analog converter (A / D converter) and P2 of a digital signal.

FIG. 6 is a block diagram showing a part of a program stored in a DSP inside the SCB shown in FIG. 2 and shows an example of a valid and reactive power calculation program.

FIG. 7 is a block diagram illustrating the hardware configuration of the SCB shown in FIG. 2, and includes an external signal input unit (ETP), a digital control processor, a digital signal processing processor, various memory devices, a power supply circuit, and the like. Same as described.

Fig. 8 shows the internal configuration of the input / output redundancy TMR I / O and the main operator, where one I / O module is composed of three circuits that are electrically independent, and includes three circuits of the auto spare module. It consists of an input / output circuit. The main control processors (Main Processors A, B, and C) inside the controller share the calculation result with the data input through the internal Tri Bus.

FIG. 9 shows a front view of the SCB shown in FIG. 2 and an internal view of the printed circuit board and a portion of a program stored in the process.

As shown in FIG. 9, the SCB includes a redundant power supply card, a monitor card, and a triplex signal processing card.

Although the technical spirit of the present invention has been described above with reference to the accompanying drawings, this will be described as an exemplary embodiment of the present invention by way of example and is not intended to limit the present invention. In addition, it is a matter of course that various modifications and variations are possible without departing from the scope of the technical idea of the present invention by anyone having ordinary skill in the art.

1 is a block diagram of a digital control system for synchronous generator voltage control according to an embodiment of the present invention;

FIG. 2 is a connection block diagram of a signal transformer, an SCB, and a controller included in the digital control system for synchronous generator voltage control of FIG.

3 is a detailed block diagram of the controller internal circuit shown in FIG. 2;

4 is an execution block diagram of a main control program stored in the controller shown in FIG. 2;

5 is an internal hardware signal connection diagram of the SCB shown in FIG.

6 is a block diagram showing a part of a program stored in a DSP inside the SCB shown in FIG. 2;

7 is a hardware block diagram of the SCB shown in FIG. 2;

8 is an internal configuration diagram of an input / output six-time TMR I / O and a main operator, and

9 is a front view of the SCB shown in FIG. 2 and an internal view of the printed circuit board and a portion of a program stored in the process.

Claims (5)

Digital control system for synchronous generator voltage control, A digital controller for performing a main control operation for controlling the output voltage and reactive power of the generator; A signal processing system that measures the voltage, power, field voltage, field current, frequency, and phase of the generator, converts the signal into a standard signal suitable for the digital controller, and transmits the signal to the digital controller; A thyristor phase control rectifier for converting AC power into DC power according to the magnitude of the signal of the digital controller; A generator voltage / current transformer for detecting the voltage and current of the generator; A field voltage / current detector for detecting signals of voltage and current of the field circuit; And An MMI system for monitoring operation data and performing system operations; And said digital controller and said signal processing system are tripled. delete The synchronous generator voltage control digital control system according to claim 1, wherein the digital controller is a general-purpose PLC controller. 2. The digital control system of claim 1, wherein the digital controller receives signals from the tripled signal processing system and selects an intermediate value thereof as a standard signal. The system of claim 4, wherein when a problem occurs in any one of the tripled signal processing systems, the signal processing system in which the problem occurs transmits a fault signal to the triplex digital controller. In response, the signal of the signal processing system in which the Fault signal is generated is excluded, and the maximum or minimum value is selected from the values of two signals from other signal processing systems, and this is selected as a standard signal. When the Fault signal is generated again in any one of the two signals, the signal processing system in which the Fault signal is generated is excluded again and overall control is performed to the remaining signal processing system. Control system.

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