KR101085175B1 - An emergency diesel generator digital excitation system for nuclear power plant using digital triplication controller and duplication rectifier, method for changing operating mode thereof and method for rapidly starting thereof - Google Patents

Abstract

The present invention receives a special input signal is processed into a generator terminal voltage, active / reactive power, generator frequency, field voltage and field current signal and the like standard signal (0-10) matching the input module of the triplex controller 40 [Vdc] and output, the input and output signal processing unit 40 configured in an analog manner;

When three channels are synchronized with each other and two channels are stopped, normal operation is possible, and the operation data necessary for operating the emergency diesel generator (GEN) is received through the digital input / output module, the analog input / output module, and the like. The thyristor of the first and second rectifiers 1-1 and 1-2 is commanded to open and close the field circuit breakers 52-1 and 52-2, and receives a standard signal output from the input / output signal processor 40. A triple controller 60 for controlling the magnitude of the terminal voltage of the emergency diesel generator by transmitting a firing signal to control the magnitude of the DC power;

First and second call cards 11-1 and 11-2 for receiving a thyristor control signal transmitted from the triplex controller 60 and finally converting the thyristor control signal to a gate call signal of the thyristor, and the first and second calls; First and second semi-converters 10-1 and 10 for converting three-phase AC power input from PPT to DC power by the gate call signal of the thyristor output from the two-call cards 11-1 and 11-2. A second and second rectifiers (1-1,1-2) configured to be dualized into two channels and bear a load in half, and if a failure occurs on one side, the other side is dedicated to the load;

Simultaneously input according to the excitation system start command received from the upper system (ECP) to apply a DC power to the generator field to induce the generator terminal voltage, and the first and second rectifiers (1) through the PCT and PPT An initial excitation magnetic contactor 31 and first and second field circuit breakers 52-1 and 52-2 for applying DC power to the field through -1, 1-2;

First and second switches 72-1 and 72-2 for opening and closing input sides of the first and second rectifiers 1-1 and 1-2;

An initial excitation resistor 32 for dropping the 125V battery voltage at the initial stage of startup and applying it to the field;

A field current X-DCR 30-1 that receives the field current signal 0-100 [mVdc] and outputs it as 0-10 [Vdc];

A field voltage X-DCR 30-2 that receives the field voltage 0-300 [Vdc] and outputs it as 0-10 [Vdc];

SH is a shunt (Shunt), digital triplex controller and redundant rectifier, characterized in that it comprises a shunt (SH) for outputting 0-100 [mVdc] when the field current 0-300 [Adc] flows on the input side It is an emergency excitation generator digital excitation system of used nuclear power plant.

Description

Emergency diesel generator digital excitation system of nuclear power plant using digital triple controller and redundant rectifier, operation mode change method, and rapid start method METHOD FOR CHANGING OPERATING MODE THEREOF AND METHOD FOR RAPIDLY STARTING THEREOF}

The present invention relates to an emergency diesel generator digital excitation system of a nuclear power plant using a digital triple controller and a redundant rectifier, a method of changing its operation mode, and a rapid start method.

Emergency diesel generator excitation system of nuclear power plant receives three phase AC power and converts it into DC power using three phase full wave rectifier. This is to control the size of the DC power generated by controlling the firing angle of the thyristor in the three-phase full-wave rectifier to ultimately control the emergency diesel generator terminal voltage and the reactive power.

The emergency diesel generator excitation system is an essential safety facility that is directly related to reactor cooling, and its quality assurance activities are strictly controlled, requiring careful attention to its construction and operation. In other words, it is not practical to apply digital system to nuclear safety level because equipment verification test and software verification and verification activities should be performed. Thus, there is a need for specific devices for applying digital systems.

The present invention has been invented in view of the above, and adopts a triple controller hardware proven reliability while developing an existing single channel analog excitation system into a triple digital excitation system, and the emergency diesel in the triple controller hardware Digital excitation system of nuclear power plant using digital triple redundancy controller and redundant rectifier that can be applied to the site by implementing algorithm and rectifier to adjust terminal voltage of generator, method of changing operation mode, and The purpose is to provide a maneuvering method.

The present invention for achieving the above object,

Standard signal (0-10 [Vdc]) matching the input module of triple controller 40 by processing special input signal into generator terminal voltage, active / reactive power, generator frequency, field voltage and field current signal Outputting, but the input and output signal processing unit 40 configured in an analog manner;

When three channels are synchronized with each other and two channels are stopped, normal operation is possible, and the operation data necessary for operating the emergency diesel generator (GEN) is received through the digital input / output module, the analog input / output module, and the like. The thyristor of the first and second rectifiers 1-1 and 1-2 is commanded to open and close the field circuit breakers 52-1 and 52-2, and receives a standard signal output from the input / output signal processor 40. A triple controller 60 for controlling the magnitude of the terminal voltage of the emergency diesel generator by transmitting a firing signal to control the magnitude of the DC power;

First and second call cards 11-1 and 11-2 for receiving a thyristor control signal transmitted from the triplex controller 60 and finally converting the thyristor control signal to a gate call signal of the thyristor, and the first and second calls; First and second semi-converters 10-1 and 10 for converting three-phase AC power input from PPT to DC power by the gate call signal of the thyristor output from the two-call cards 11-1 and 11-2. A second and second rectifiers (1-1,1-2) configured to be dualized into two channels and bear a load in half, and if a failure occurs on one side, the other side is dedicated to the load;

Simultaneously input according to the excitation system start command received from the upper system (ECP) to apply a DC power to the generator field to induce the generator terminal voltage, and the first and second rectifiers (1) through the PCT and PPT An initial excitation magnetic contactor 31 and first and second field circuit breakers 52-1 and 52-2 for applying DC power to the field through -1, 1-2;

First and second switches 72-1 and 72-2 for opening and closing input sides of the first and second rectifiers 1-1 and 1-2;

An initial excitation resistor 32 for dropping the 125V battery voltage at the initial stage of startup and applying it to the field;

A field current X-DCR 30-1 that receives the field current signal 0-100 [mVdc] and outputs it as 0-10 [Vdc];

A field voltage X-DCR 30-2 that receives the field voltage 0-300 [Vdc] and outputs it as 0-10 [Vdc];

SH is a shunt (shunt) of a nuclear power plant using a digital triple controller and a redundant rectifier having a shunt (SH) that outputs 0-100 [mVdc] when the field current 0-300 [Adc] flows on the input side. Features an emergency diesel generator digital excitation system.

In addition, the present invention is characterized in that a failure category of the alarm circuit is configured into four categories of power system failure, restriction algorithm failure, rectifier failure, and input / output signal processing (SCB) failure.

In addition, the present invention uses a connection mechanism so that the connection of the first and second power line terminal blocks 6-1 and 6-2 is short-circuited by using a connection mechanism and a cable, and the AC three-phase which is an excitation power source is not mixed. It is characterized in that the connection.

In addition, the present invention, the constant power is input to the storage battery 125 [Vdc] and the emergency power supply that can be used only during normal operation of the emergency diesel generator is less than 125 [Vdc] rectified DC power using a transformer and a separate transformer There is no fluctuation of the power supply, and the precision load is characterized by converting the input to 125 [Vdc] to a smaller level.

In another aspect, the present invention is characterized in that the signal is sent to the indicator and the upper system (ECP) to detect the failure location of the redundant power supply and to detect the loss of the 125 [Vdc] input power.

In addition, the present invention is characterized in that the voltage drop means for dropping the voltage when the voltage is greater than a predetermined size when the excessive voltage occurs in parallel to the input side of the power supply.

In addition, the present invention is characterized in that the voltage drop means comprises a series connection of the zener diode (Z) and the resistor (R).

The present invention also detects the magnitude of the three generator phase voltage during normal operation in which the generator breaker is input, and if the voltage drop in a single phase or more occurs a certain size or the whole is lost, the operation mode in the automatic mode manual mode Characterized in that the transfer to.

Method for changing the operation mode of the emergency diesel generator digital excitation system of a nuclear power plant using a digital triple controller and redundant rectifier according to the present invention,

Setting the automatic mode in the normal operation state of the excitation system, turning on the generator breaker, and determining whether each phase voltage is greater than 50% (S1 to S3);

If each phase voltage is less than 50% in step S3, changing the operation mode from the automatic mode to the manual mode (S4);

If each phase voltage is greater than 50% in step S3, comparing each phase voltage to determine whether a certain deviation occurs (S5);

Changing a driving mode from an automatic mode to a manual mode when a predetermined deviation occurs as a result of comparing the phase voltages in the step S5;

When a certain deviation does not occur as a result of comparing the phase voltages in the step S5, it is characterized in that it comprises a step (S7) for maintaining the automatic mode as it is.

In addition, the emergency diesel generator digital excitation system of the nuclear power plant using the digital triple controller and redundant rectifier according to the present invention,

It is an emergency diesel generator of a nuclear power plant using a digital triple control controller and a redundant rectifier that prevents overshoot during start-up by using the soft start method.

This method,

Applying an emergency start command of the emergency diesel generator and determining whether the engine speed is 200 rpm (S11 and S12);

If it is determined in step S12 that the engine speed is 200rpm, step (S13) to process as a start failure after a predetermined time has passed;

If it is determined in step S12 that the engine speed is 200 rpm, generating an excitation system start command, applying an initial excitation by applying a field circuit breaker, and setting the soft start mode to increase to a set ramp value (S14 to S16). ;.

Determining whether 8 seconds have elapsed and, if 8 seconds have not elapsed, returning to the step S16 and setting the soft start mode to increase to the set ramp value (S17);

If it is determined that 8 seconds have elapsed in step S17, releasing the soft start and establishing 1pu with respect to the generator terminal voltage to block initial excitation (S18);

Determining whether the overshoot exceeds 110% (S19);

If the overshoot in step S19 does not exceed 110%, determining whether the motor is operated within a specified voltage and a specified frequency within 10 seconds after the rapid start command (S20);

If it is determined in step S20 that the operation is within the specified voltage and the specified frequency within 10 seconds after the rapid start command, determining that the rapid start requirement is satisfied (S21);

Stopping the excitation system when it is determined in step S19 that the overshoot exceeds 110%, or when it is determined in step S20 that the overshoot is not operated within the specified voltage and the specified frequency within 10 seconds after the rapid start command. (S23);

Adjusting the soft start ramp ratio and adjusting gain for starting the PI (proportional-integral) controller (S23, S24);

It is determined whether the adjustment result in the step S23 and step S24 was finally confirmed, and if the adjustment result is not finally confirmed, proceeding to the step S12 and proceeding the rapid start process of the emergency diesel generator ( S25) and;

When the adjustment result is finally confirmed in the step S25, the engine is stopped, and the process proceeds to the step S11, characterized in that it comprises a step (S26) for proceeding the emergency starting process of the emergency diesel generator again.

In addition, the present invention is characterized in that the adjustment of the gain for starting the PI (proportional-integral) controller in step S24 sets the gain of the PI controller separately from startup and normal operation in order to satisfy the time requirement of 10 seconds. do.

According to the present invention, by consisting of three independent channel controller (triple) and two channel rectifier, the reliability of the equipment is greatly increased.

In addition, it can be directly applied to the emergency diesel generator excitation system (safety grade) of nuclear power plants, and the individual application and integration of the emergency diesel generator's governor and engine control system will be possible in the future.

In addition, in case of emergency diesel generator excitation system of nuclear power plant, the demand for safety grade digital excitation system is increasing as it is difficult to secure spare parts of existing analog system. And licensing requirements.

Moreover, the present invention can be directly applied to three units (6 units, 2 units per unit) of nuclear power plants, and 10 units can be applied with some modifications, thereby expanding into domestic and overseas markets in the future. It is also possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, the excitation system receives a three-phase AC power source, converts it into a DC power source using a three-phase full-wave rectifier, and adjusts the magnitude of the DC power generated by controlling the firing angle of the thyristor in the three-phase full-wave rectifier. Ultimately, the magnitude of the emergency diesel generator terminal voltage is controlled.

That is, in the present invention, in order to secure the reliability of the emergency diesel generator excitation system, the controller is configured as triple, and the rectifier is configured as dual.

It also simplifies the power supply structure to minimize failures. That is, a power supply is required for a circuit for monitoring the health of the analog output module of the triplex controller, and a power supply for the input and output signal processing system that makes a standard signal input to the triplex controller is also used. . Also use the power of the call card. In addition, to reduce the software verification and verification activities, the input and output signal processing system is configured in an analog manner.

FIG. 1 is a configuration diagram of an emergency diesel generator digital excitation system of a nuclear power plant according to the present invention, and illustrates an apparatus arrangement for passing a device verification test.

In other words, the existing single channel analog excitation system was developed as a triple digital excitation system. It adopts a proven triple control controller hardware and implements an algorithm that can adjust the terminal voltage of emergency diesel generators. The input / output signal processing system that makes the standard analog input signal with the triple controller and its power supply also reduce the failure factor by unifying the analog module scan power and rectifier firing card power of the triple controller.

On the other hand, the method of constructing the emergency diesel generator excitation system of a nuclear power plant is different from the existing excitation system, so safety is a top priority. It is characterized by one function rather than multifunction.

That is, the emergency diesel generator excitation system is composed of a controller cubicle (1) and a rectifier cubicle (2), the excitation power source is input to the rectifier cubicle (2) and the first and second field circuit breakers (52-1, 52-) 2) via the controller cubicle 1 via the first and second semi-converters 10-1 and 10-2 and the first and second rectifier output side switches 72-1 and 72-2. Supplied to the generator field.

The triplex controller 60 (refer to FIG. 2) receives various control signals through the input / output signal processor 40 (SCB) and the input / output module and sends the call signal to the first and second call cards 11-1 and 11-2. The first and second semi-converters 10-1 and 10-2 of the SCR-Diode combination are sent by transmitting the.

In FIG. 1, the alarm lamp 3 performs a function of ringing an alarm of the excitation system, and the first and second power supplies 4-1 and 4-2 are provided with the input / output signal processor 40 and the first and second devices. Power is supplied to the firing cards 11-1 and 11-2 and various relays.

In addition, the triplex controller 60 enables normal operation even when three channels are stopped up to two channels while synchronizing with each other. Receives the operation data necessary to operate the emergency diesel generator through the digital input / output module and the analog input / output module, and opens and commands the first and second field circuit breakers 52-1 and 52-2, and calls the gate of the thyristor of the rectifier. It ultimately plays a key role in controlling generator terminal voltage.

The operation switch 5 operates functions for opening and closing of the first and second field circuit breakers 52-1 and 52-2, returning to the alarm, and the like.

The input / output signal processing unit 40 (SCB) receives the generator terminal voltage and the generator armature current to generate standard signals such as generator active power, reactive power, and frequency.

Further, the first and second call cards 11-1 and 11-2 transmit SCR gate call signals of the first and second semi-converters 10-1 and 10-2 of the SCR-Diode combination.

The first and second semi-converters 10-1 and 10-2 of the SCR-Diode combination receive a three-phase AC power and generate a DC power by applying a firing signal to three gates of the SCR.

The first and second power line terminal blocks 6-1 and 6-2 are input side three-phase power lead wire terminals of the first and second rectifiers 1-1 and 1-2.

The upper system (ECP) performs a function of sending a signal to the central control room due to the gathering of cubicles and various alarms for controlling the engine.

Figure 2 shows the configuration of the emergency diesel generator digital excitation system 100 according to the present invention, in the configuration of Figure 2 in order to ensure reliability the controller is tripled (normal operation even if stopped up to two of the three independent channels) Possible structure), and the rectifier part is composed of double channel (that is, it consists of two channels of the first rectifier and the second rectifier, and divides the load by half, and if one side breaks down, the other side is dedicated to the load). .

In order to reduce the software verification and verification activities as much as possible, the analog input / output signal processing unit that generates the standard signal (0-10 [Vdc]) input to the digital controller is configured.

During operation, in order to stabilize the system by unifying control power rather than improving accuracy, a signal converter (field voltage X-DCR) is used instead of DC PT (direct voltage transformer) as a field voltage (rectifier output voltage) acquisition device. As a rectifier output current acquisition device, a signal converter (field current X-DCR) is also used instead of Hall CT (current transformer).

When the emergency diesel generator (GEN) of the nuclear power plant receives the start signal, the engine of the emergency diesel generator (GEN) is operated. When the engine reaches a constant speed, the signal to start the excitation system is the upper system (ECP). Is received from When the signal for starting the excitation system is received from the upper system (ECP) as described above, the initial magnetic contactor 31 and the first and second field circuit breakers 52-1 and 52-2 are inputted to the input / output signal processor. The generator terminal voltage is induced as the thyristors (not shown) of the first and second rectifiers 1-1 and 1-2 are fired by the control signals generated by the 40 and the triple controller 60. .

The input / output signal processing unit 40 receives a special input signal (generator terminal voltage (PT), terminal current (CT), field voltage X-DCR and field current X-DCR signal, etc.) to the generator terminal voltage, active / reactive power , And processed into a generator frequency, field voltage and field current signal, and outputs a standard signal (eg 0-10 [Vdc]) suitable for the input module of the triplex controller 60, and is configured in an analog manner.

Man-machine interface (MMI) is required for effective operation of digital systems. Due to the special circumstances of nuclear power plant emergency diesel generator excitation system, existing interfaces are added and alarm circuits are added.

That is, upon receiving the excitation system start command from the upper system (ECP), the initial magnetic contactor 31, the first and second field circuit breakers 52-1 and 52-2 are simultaneously supplied to supply DC power to the generator field. When applied, the generator terminal voltage starts to be induced. The induced power is supplied to the field through the first and second rectifiers 1-1 and 1-2 via a power current transformer (PCT) and a power potential transformer (PPT).

In this case, the triplex controller 60 combines the first and second rectifiers 1-1 and 1-2 by combining the generator terminal voltage, the armature current, the field voltage, the field current signal, etc. received through the input / output signal processor 40. The generator terminal voltage is finally controlled by sending the thyristor firing signal of) and controlling the magnitude of DC power.

In Fig. 2, reference numerals 72-1 and 72-2 denote first and second rectifiers 1-1 and 1-2 input-side switchgear, 32 is an initial excitation resistance, and a 125V battery voltage To descend and apply to the field. Reference numeral SH denotes a shunt, which is a device (direct current input signal converter) that outputs 0-100 [mVdc] when field current 0-300 [Adc] flows on the input side.

On the other hand, the field current X-DCR (30-1) is a device (direct current input signal converter) for receiving the field current signal 0-100 [mVdc] to output to 0-10 [Vdc]. In addition, the field voltage X-DCR 30-2 is a device (direct current input signal converter) that receives the field voltage 0-300 [Vdc] and outputs it to 0-10 [Vdc].

In addition, the triple controller 60 is configured to operate normally even when three channels are stopped and up to two channels are synchronized with each other. The first and second field circuit breakers 52-1 and 52-2 are opened and received by receiving operation data necessary for operating the emergency diesel generator GEN through the digital input / output module and the analog input / output module, and the like. It plays the role of controlling the gate of the thyristor of the two rectifiers (1-1, 1-2) and ultimately plays the key role of controlling the generator terminal voltage.

3 is a configuration diagram of the alarm circuit of the emergency diesel generator digital excitation system according to the present invention.

As shown in FIG. 3, the alarm circuit is divided into four failure categories and grouped related systems (power system failure, restriction algorithm failure, rectifier failure, input / output signal processing (SCB) failure).

In addition, the final alarm signal is transmitted through the relay in the controller cubicle 1 (see FIG. 1), and is normally kept in an excited state, and when the corresponding failure occurs or the input power is lost, the excitation system alarm relay An element 101 is provided to transmit an alarm signal to the higher system ECP via the excitation system alarm relay 101. In addition, the alarm lamp 3 is also arranged on the front part of the controller cubicle 1 as shown in FIG. 1 so that an operator can recognize it quickly.

The power system failure is an alarm when a power supply failure, excitation system trip request occurs, rectifier output side switch failure, triple controller alarm failure, field breaker open failure, etc. occur.

The restriction algorithm failure will sound an alarm when the confectionery restriction function is activated, the overexcitation restriction function or the underexcitation restriction function is operated.

The rectifier failure may occur when the first rectifier 1-1 is tripped, the second rectifier 1-2 is tripped, the first field circuit breaker 52-1 fails, or the second field circuit breaker 52-2 fails. An alarm will sound.

The SCB fault receives the signals from the generator PT and CT and generates the generator terminal voltage, the terminal current and the generator frequency as standard signals again. Generator voltage deviation, active power deviation, reactive power deviation, and frequency deviation signals are generated to generate an alarm. It also makes three signals of field voltage and field current so that an alarm sounds when the deviation of these signals is over a certain size. In addition, an alarm occurs when the SCB is removed.

In Fig. 3, reference numeral OR denotes a logic circuit that outputs output "1" when any of the inputs becomes "1", and & denotes a logic circuit that outputs output "1" when all inputs are "1". to be. In addition, SR is a set-reset flip-flop circuit, and once "1" is input to the set terminal, it is a circuit that holds "1" until "1" enters the reset terminal.

4 shows a method of connecting terminals of a three-phase power cable at the input side of the first and second rectifiers according to the present invention, which is a method of connecting the first and second power line terminal blocks 6-1 and 6-2. Short-circuit processing is done using the connecting device and cable, not the booth method, so that it does not violate the safety of the design standard accident (earthquake, etc.) or work. In addition, the AC three-phase phase, which is an excitation power source, is connected by using a short or long connecting mechanism so as not to touch.

In other words, the terminal wiring method of the power supply cable of the rectifier input side is not a busbar type, and is made so that the part drawn out from the terminal is different and connected by using a specially manufactured connection mechanism that can prevent contact with each other. It can be prevented.

5 is a flow chart illustrating a method of changing an operation mode of a digital excitation system of an emergency diesel generator of a nuclear power plant according to the present invention.

The automatic operation mode of the excitation system operates by feeding back the generator terminal voltage, and the excitation system manual operation mode operates by receiving the generator field current. The emergency diesel generator excitation system is basically operated in automatic mode. Only one pair of generator PTs (one in three phases and three in each) is installed. Therefore, when the generator PT fuse is blown, there is a fear of overvoltage trip because the fed back generator terminal voltage becomes small. In such a case, it is possible to operate stably under the operator's judgment to switch the operation mode. However, in order to prevent automatic switching of the operation mode in the transition period (starting or stopping), the contact of the generator breaker is put into operation under the switching condition.

Hereinafter, each step of the excitation system operation mode changing method will be described.

First, it is set to the automatic mode in the normal operation state of the excitation system (step S1), and then the generator breaker is put in (step S2), and it is then determined whether each phase voltage is greater than 50% (step S3).

If each phase voltage is less than 50% in step S3, the operation mode is changed from the automatic mode to the manual mode (step S4).

If each phase voltage is greater than 50% in step S3, it is determined whether a certain deviation occurs by comparing each phase voltage (step S5).

When a certain deviation occurs as a result of the comparison of the phase voltages in step S5, the operation mode is changed from the automatic mode to the manual mode (step S6).

If the constant deviation does not occur as a result of the comparison of the phase voltages in step S5, the automatic mode is maintained as it is (step S7).

Thus, when only three sets of generator PT (voltage transformer) fuses are installed, three fuses of the phase voltage of the generator are detected during normal operation (when the generator breaker is inserted) by focusing on blown fuses one by one. If the voltage drop occurs in a single phase or more, or the whole is lost (that is, the phase voltage is less than 50%), the operation mode can be switched from the automatic mode to the manual mode for stable system operation. Done.

6 is a flowchart for explaining a rapid starting (commissioning) method of the emergency diesel generator according to the present invention.

Soft start method is used to reduce the overshoot in the past when the analog system has been started.In case of failing to meet the rapid start requirement of 10 seconds, the PI (proportional-integral) controller gain is used for starting and normal operation. It is possible to set it by display and adjust the gain of starting PI controller.

Hereinafter, each step of the rapid start (commissioning) method of the emergency diesel generator will be described sequentially.

First, a sudden start command of the emergency diesel generator is applied (step S11), and it is determined whether the engine speed is 200 rpm (step S12).

If it is determined in step S12 that the engine speed is 200 rpm, then a predetermined time has elapsed and then a start failure is processed (step S13).

On the other hand, if it is determined in step S12 that the engine speed is 200 rpm, an excitation system start command is generated (step S14), the magnetic field circuit breaker is input to apply an initial excitation (step S15), and the soft start increases to the set ramp value. The mode is set (step S16).

Subsequently, it is determined whether 8 seconds have elapsed (step S17), and when 8 seconds have not elapsed, the flow returns to step S16 to set the soft start mode to increase to the set ramp value. On the other hand, when it is determined that 8 seconds have elapsed in step S17, the soft start is released and 1 pu is established for the generator terminal voltage to block the initial excitation (step S18).

Subsequently, it is determined whether the overshoot exceeds 110% (step S19), and if the overshoot does not exceed 110%, it is determined whether the overshoot is operated within the specified voltage and the specified frequency within 10 seconds after the rapid start command. It judges (step S20).

If it is determined in step S20 that the operation is made within the specified voltage and the specified frequency within 10 seconds after the rapid start command, it is determined that the rapid start requirement is satisfied (step S21).

On the other hand, if it is determined in step S19 that the overshoot exceeds 110%, or if it is determined in step S20 that the overshoot is not operated within the specified voltage and the specified frequency within 10 seconds after the rapid start command, the excitation system is deactivated. It stops (step S23).

Then, the soft start ramp ratio is adjusted (step S23), the PI (proportional-integral) controller is adjusted for gain (step S24), and whether the adjustment results in the steps S23 and S24 are finally confirmed. (Step S25).

When the adjustment result is finally confirmed in the step S25, the engine is stopped (step S26), the process proceeds to the step S11 to resume the rapid start process of the emergency diesel generator, and the adjustment result is finally confirmed in the step S25. If not, the flow proceeds to step S12 to proceed with the emergency starting process of the emergency diesel generator.

In this way, the generator terminal voltage set value is ramped up to avoid overshoot, to prevent damage to the generator, and to meet the rapid start requirements (operating within the specified voltage and the specified frequency within 10 seconds after the start command). A soft start method is adopted.

There are two kinds of emergency diesel generators: rapid start and slow start. The quick start method means that the inverter operates at a specified voltage (90 to 110% of the rated voltage) and a specified frequency (98 to 102% of the rated frequency) within 10 seconds after detecting a signal such as an essential bus short voltage relay operation. The system is operated with a field circuit breaker at 200 rpm, which is 44% of the engine's rated speed, and the slow start method does not start in a short time to protect the engine, but starts slowly to check whether the engine is started. Field breaker at 96% of the speed).

The soft-start method has the advantage of avoiding sudden overshoot, while the PI (proportional-integral) controller gain is normally used for start-up and normal if it is difficult to operate within the specified conditions within 10 seconds after the start command, which is one of the rapid start requirements. There are two ways of adjusting the gain for starting.

7 is a diagram illustrating a redundant configuration of a power supply and an overvoltage preventing device according to the present invention.

The configuration shown in FIG. 7 is for simply and reliably configuring a power supply. The control power is unified to a DC power supply 125 [V], and an AC power supply drawn from an excitation power supply (emergency diesel generator excitation transformer) as a reserve power supply. Rectify to 115 [Vdc]. This is to prevent the power supply from repeating energization and interruption during normal operation. In other words, the control power of the emergency diesel generator excitation system is received from the storage battery of 125 [V dc], and as the reserve power, the voltage of the output is reduced and rectified after the emergency diesel generator is generated.

In addition, due to the characteristics of the lottery-type excitation system, when a short circuit accident occurs on the generator output side, excessive voltage may be induced in the excitation power supply. The power loss alarm is also configured using a control relay Ry.

8 illustrates a configuration of a power supply failure detection circuit according to the present invention, and by configuring a failure detection circuit of the power supply as shown in FIG. 8, the failure of the power supply can be confirmed even in a field panel (see FIG. 1).

That is, during normal operation, the green LED 80 is turned on to the power supply, and when a failure occurs, the green LED 80 is turned off and the yellow LED 90 is turned on. In addition, when the fault is resolved, the green LED 80 which is turned off is turned on, and the yellow LED 90 is continuously turned on so that the yellow LED 80 is operated when the operator operates the return button after recognizing the fault condition. Configure to turn off.

This is to check if any one of the two redundant power supplies has failed even if the failure occurs momentarily and then disappears. In FIG. 8, reference numeral Q denotes a semiconductor switch, and the 24V DC power supply is cut off when a constant deviation deviates, and functions as a switch that is turned on when operated within a constant deviation.

That is, as shown in FIG. 7, the control power is supplied to the storage battery 125 [Vdc] and rectified by using a transformer separate from the excitation transformer and a separate power supply (usable only during the emergency operation of the emergency diesel generator). One DC power supply is made smaller than 125 [Vdc] so that there is no fluctuation of power. Furthermore, the precision load such as a control card receives the 125 [Vdc] and converts it to a smaller level (24 [Vdc], etc.). At this time, in order to monitor the reliability of the power supply, a failure detection circuit is implemented as shown in FIG. And / or configured in software to send a signal to the indicator and upper system (ECP) to detect the fault location of the redundant power supply and to detect the loss of 125 [Vdc] input power.

The power supply failure detection circuit according to the present invention is a circuit installed inside the power supply 102, and the semiconductor switch Q is a power supply 102 when the output power 24 [Vdc] deviates from a certain deviation (10%). Shut off and conduct when operated within a certain deviation.

Case 1

When the output power source 24 [Vdc] is within a certain deviation, the green LED 80 lights up, and the first control relay Ry-1 is excited. At this time, the second control relay Ry-2 maintains the device state and the yellow LED 90 also goes out.

Case 2

When the output power source 24 [Vdc] deviates from a certain deviation, the semiconductor switch Q is cut off. When the semiconductor switch Q is cut off in this manner, the first control relay Ry-1 is turned off and the green LED 80 is turned off. On the other hand, the second control relay Ry-2 is excited, the yellow LED 90 is turned on, and the power supply 102 failure alarm is sent to the upper system.

Case 3

When a fault occurs momentarily and is restored, the semiconductor switch Q is turned on so that the green LED 80 is turned on and the first control relay Ry-1 is excited (the yellow LED 90 remains lit and the second is turned on). Control relay (Ry-2) excitation hold)

Case 4

When the operator recognizes the situation and presses the return button in the field while the alarm condition is released (operation within a certain deviation of the power supply output voltage), the yellow LED 90 is turned off and the green LED 80 is turned on. The first control relay Ry-1 is excited and the second control relay Ry-2 is demagnetized.

1 is a configuration diagram of an emergency diesel generator digital excitation system of a nuclear power plant according to the present invention,

2 is a view showing the configuration of an emergency diesel generator digital excitation system 100 according to the present invention,

3 is an alarm circuit diagram of an emergency diesel generator digital excitation system according to the present invention;

4 is a view showing a terminal connection method of a three-phase power cable on the input side of the first and second rectifiers according to the present invention;

5 is a flow chart for explaining a method of changing the operation mode of the digital excitation system of the emergency diesel generator of the nuclear power plant according to the present invention,

6 is a flowchart for explaining a rapid start (commissioning) method of the emergency diesel generator according to the present invention;

7 is a view showing a redundant configuration of the power supply and the overvoltage protection device according to the present invention,

8 is a view showing the configuration of a power supply failure detection circuit according to the present invention.

Claims (11)

Standard signal (0-10 [Vdc]) matching the input module of triple controller 40 by processing special input signal into generator terminal voltage, active / reactive power, generator frequency, field voltage and field current signal Outputting, but the input and output signal processing unit 40 configured in an analog manner; When three channels are synchronized with each other and two channels are stopped, normal operation is possible, and the operation data necessary for operating the emergency diesel generator (GEN) is received through the digital input / output module, the analog input / output module, and the like. The thyristor of the first and second rectifiers 1-1 and 1-2 is commanded to open and close the field circuit breakers 52-1 and 52-2, and receives a standard signal output from the input / output signal processor 40. A triple controller 60 for controlling the magnitude of the terminal voltage of the emergency diesel generator by transmitting a firing signal to control the magnitude of the DC power; First and second call cards 11-1 and 11-2 for receiving a thyristor control signal transmitted from the triplex controller 60 and finally converting the thyristor control signal to a gate call signal of the thyristor, and the first and second calls; First and second semi-converters 10-1 and 10 for converting three-phase AC power input from PPT to DC power by the gate call signal of the thyristor output from the two-call cards 11-1 and 11-2. A second and second rectifiers (1-1,1-2) configured to be dualized into two channels and bear a load in half, and if a failure occurs on one side, the other side is dedicated to the load; Simultaneously input according to the excitation system start command received from the upper system (ECP) to apply a DC power to the generator field to induce the generator terminal voltage, and the first and second rectifiers (1) through the PCT and PPT An initial excitation magnetic contactor 31 and first and second field circuit breakers 52-1 and 52-2 for applying DC power to the field through -1, 1-2; First and second switches 72-1 and 72-2 for opening and closing input sides of the first and second rectifiers 1-1 and 1-2; An initial excitation resistor 32 for dropping the 125V battery voltage at the initial stage of startup and applying it to the field; A field current X-DCR 30-1 that receives the field current signal 0-100 [mVdc] and outputs it as 0-10 [Vdc]; A field voltage X-DCR 30-2 that receives the field voltage 0-300 [Vdc] and outputs it as 0-10 [Vdc]; SH is a shunt (Shunt), digital triplex controller and redundant rectifier, characterized in that it comprises a shunt (SH) for outputting 0-100 [mVdc] when the field current 0-300 [Adc] flows on the input side Emergency excitation generator digital excitation system of used nuclear power plant. 2. The digital triple controller and redundant rectifier according to claim 1, wherein the failure categories of the alarm circuit are configured into four categories: power system failure, restriction algorithm failure, rectifier failure, and input / output signal processing (SCB) failure. Emergency diesel generator digital excitation system at nuclear power plant. The connection mechanism according to claim 1, wherein the connection of the first and second power supply terminal blocks 6-1 and 6-2 is short-circuited using a connection mechanism and a cable, and the connection mechanism is not mixed with an alternating current three phases. Emergency excitation generator digital excitation system of a nuclear power plant using a digital triple controller and redundant rectifier, characterized in that the connection using. The method of claim 1, wherein the constant power is input to the storage battery 125 [Vdc] and the reserve power available only during normal operation of the emergency diesel generator is greater than 125 [Vdc]. An emergency diesel generator digital excitation system of a nuclear power plant using a digital triplex controller and a redundant rectifier, characterized in that the input is 125 [Vdc] and converted to a smaller level in a precision load. The digital triple controller according to claim 1, wherein a signal is transmitted to an indicator light and an upper system (ECP) to detect a failure of the redundant power supply and detect whether or not the 125 [Vdc] input power is lost. Emergency Exciting Generator Digital Excitation System in Nuclear Power Plants with Dual Rectifiers. 2. The emergency of a nuclear power plant using a digital triple controller and a redundant rectifier, characterized in that the voltage drop means for dropping the voltage when the voltage is greater than a rated voltage in the event of excessive voltage is connected in parallel to the input side of the power supply. Diesel Generator Digital Excitation System. The emergency excitation diesel generator digital excitation system of a nuclear power plant using a digital triple controller and a redundant rectifier, characterized in that the voltage drop means is composed of a series connection of a zener diode (Z) and a resistor (R). According to claim 1, When the three generator phase voltage magnitude is sensed during normal operation in which the generator breaker is applied, if the voltage drop in a single phase, or more than a certain amount or the whole is lost, the operation mode is automatically operated in the automatic mode Emergency excitation generator digital excitation system of a nuclear power plant using a digital triple controller and redundant rectifier, characterized in that the transfer to the mode. Setting the automatic mode in the normal operation state of the excitation system, turning on the generator breaker, and determining whether each phase voltage is greater than 50% (S1 to S3); If each phase voltage is less than 50% in step S3, changing the operation mode from the automatic mode to the manual mode (S4); If each phase voltage is greater than 50% in step S3, comparing each phase voltage to determine whether a certain deviation occurs (S5); Changing a driving mode from an automatic mode to a manual mode when a predetermined deviation occurs as a result of comparing the phase voltages in the step S5; In the case of the step S5 as a result of the comparison of the phase voltage does not cause a certain deviation occurs, the emergency diesel of the nuclear power plant using a digital triplex controller and redundant rectifier, characterized in that it comprises a step (S7) to maintain the automatic mode as it is. How to change generator digital excitation system operation mode. It is an emergency diesel generator of a nuclear power plant using a digital triple control controller and a redundant rectifier that prevents overshoot during start-up by using the soft start method. This method, Applying an emergency start command of the emergency diesel generator and determining whether the engine speed is 200 rpm (S11 and S12); If it is determined in step S12 that the engine speed is 200rpm, step (S13) to process as a start failure after a predetermined time has passed; If it is determined in step S12 that the engine speed is 200 rpm, generating an excitation system start command, applying an initial excitation by applying a field circuit breaker, and setting the soft start mode to increase to a set ramp value (S14 to S16). ;. Determining whether 8 seconds have elapsed and, if 8 seconds have not elapsed, returning to the step S16 and setting the soft start mode to increase to the set ramp value (S17); If it is determined that 8 seconds have elapsed in step S17, releasing the soft start and establishing 1pu with respect to the generator terminal voltage to block initial excitation (S18); Determining whether the overshoot exceeds 110% (S19); If the overshoot in step S19 does not exceed 110%, determining whether the motor is operated within a specified voltage and a specified frequency within 10 seconds after the rapid start command (S20); If it is determined in step S20 that the operation is within the specified voltage and the specified frequency within 10 seconds after the rapid start command, determining that the rapid start requirement is satisfied (S21); Stopping the excitation system when it is determined in step S19 that the overshoot exceeds 110%, or when it is determined in step S20 that the overshoot is not operated within the specified voltage and the specified frequency within 10 seconds after the rapid start command. (S23); Adjusting the soft start ramp ratio and adjusting gain for starting the PI (proportional-integral) controller (S23, S24); It is determined whether the adjustment result in the step S23 and step S24 was finally confirmed, and if the adjustment result is not finally confirmed, proceeding to the step S12 and proceeding the rapid start process of the emergency diesel generator ( S25) and; When the adjustment result is finally confirmed in the step S25, the engine is stopped, and the process proceeds to the step S11, wherein the step of re-starting the rapid start process of the emergency diesel generator (S26) characterized in that it comprises a digital triple controller Emergency excitation generator digital excitation system of nuclear power plant 11. The method according to claim 10, wherein in step S24, adjustment of the gain for starting the PI (proportional-integral) controller is set so that the gain of the PI controller is divided into startup and normal operation to satisfy a time requirement of 10 seconds. Emergency excitation generator digital excitation system of nuclear power plant using digital triple controller and redundant rectifier.

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