JPS6223328A - Accesory recovery controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention has a plurality of buses receiving power from different 111 power supply systems, and when one of the power supply systems breaks down, the plant automatically switches to another healthy system. The present invention relates to an auxiliary machine control device for operating component equipment, and particularly to an auxiliary machine recovery control device that can perform optimal auxiliary machine recovery operations depending on the operational status of a plant.

[Technical background of the invention and its problems]

In recent years, large-scale fuel receiving terminals have been constructed as power generation units have become larger in capacity due to the increase in electricity demand and fuels have diversified to petroleum mustard NG, LPG, etc.

At liquefied gas fuel bases such as LNG and LPG, the liquefied gas is vaporized at the base and directly supplied to multiple power plants, so the reliability of base operations directly affects the reliability of the power plants receiving the fuel supply. It's related.

For this reason, the base's in-house power supply adopts a two-line power receiving system that receives power from two different systems, and if an external accident occurs in one system or a power outage occurs without warning, the system on the faulty side is disconnected and a bus breaker is installed. The system automatically and quickly switches power to the healthy system.

In this case, conventional methods have been used to switch between instantaneous power outage switching before the phase difference between the residual voltage on the faulty system bus and the voltage on the healthy system bus becomes large, and when the phase difference is detected and the phase difference falls within the tolerance value Phase detection method that switches, constant voltage switching method that detects when the residual voltage is less than a specified value, for example 30% of the rated value, and switches when the vector difference voltage is within 1.3P or IJ in the worst case, residual voltage 'S specified value 1. For example, a time-limited relay type is used in which the optimal time required to reach 30% or less of the rated value is measured in advance, and the time-limited relay is switched after waiting for that time plus a margin time.

However, due to the characteristics of the auxiliary equipment at the liquefied gas fuel base, the phase detection method described above has a short allowable input time of about 0.01 seconds.
Moreover, this allowable time decreases over time.

On the other hand, the closing time of the busbar connection breaker is about 0.1 degrees, and it is technically very difficult to issue a closing command in anticipation of this closing time.

In addition, in the instantaneous power outage method, if there is no phase difference between the two power supplies, the phase difference is a value that is considered safe.

For example, if the angle is within 20 degrees, the faulty system is disconnected 10.
0.02 seconds, and the minimum turn-on time for a high-speed breaker is about 0.02 seconds, which makes the timing extremely difficult, and even if possible, a high-speed breaker is required, which increases costs. Furthermore, when there is a phase difference between the two power supplies,
Depending on the type of failure, the conditions may become even more severe.

For these reasons, a low voltage switching system or a one-time relay system is generally used.

By the way, in this low-voltage switching system or one-time relay system, the residual voltage on the bus on the failure system side becomes a very small value until the bus-bar connection breaker is turned on. Therefore, when the busbar connecting breaker is turned on, a voltage of around 1P and U will be applied to the compensation motor connected to the busbar on the failed system side, so that the normal side power supply connected by the busbar connecting breaker A large inrush current flows through system Vt components such as system transformers and station busbars, which may lead to a system trip. Therefore, the minimum source of auxiliary equipment required to operate the plant, such as the supplementary air used except for the electric motor for the vaporizer seawater pump, is forcibly disconnected from the bus bar on the failed system side at the same time as the failed system is disconnected. This prevents excessive inrush current from flowing through the system components. Furthermore, the auxiliary machines that were forcibly disconnected are restored in order, starting with the most important ones, depending on the operating status of the plant, and in the end, all the auxiliary motors on the faulty system bus are in their pre-accident state and on the healthy side! ! It is designed to receive power from the power supply system.

However, if this recovery operation takes a long time, the disconnected auxiliary equipment will have to stand by without power for a long time, so the uncontrolled time will be longer compared to the various process quantities controlled by the disconnected auxiliary equipment. In some cases, this could lead to a loss of functionality as a base.

Also, if many auxiliary equipment are restored in a short period of time, there may be excessive in-plant damage to the healthy system components. I current flows, leading to failures such as equipment damage or failure to switch power. Therefore, it is desirable to have a recovery operation that comprehensively takes into account the operational status of the plant and the inrush current, and that can reproduce the state before the accident in a short period of time. Conventionally, recovery operations for such process auxiliary equipment have been carried out solely at the discretion of skilled operators. However, if an operator with low skill level performs this operation, or if a human error occurs during the operation process, the recovery operation may not be carried out properly, which may result in the plant being shut down.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to enable optimal auxiliary equipment recovery operations depending on various plant operating conditions, and to facilitate the deciphering of control know-how. It is an object of the present invention to provide an auxiliary equipment recovery control device that can easily respond to changes in the operating pattern of a plant.

[Summary of the invention]

In order to achieve such an object, the present invention provides an input device that takes in plant observation information such as the operation/stop status of each plant component equipment and various process quantities controlled by plant auxiliary equipment as input data when each power supply system is healthy. , storage means for temporarily storing the operating state of the plant obtained from the input data taken in by the input device together with the input data;
It consists of a database in which the operational status of the plant and input data stored in this storage means are accumulated together with fixed data such as various constants, and a rule base in which various information regarding the operational priorities of the plant component equipment is accumulated in advance as generation rules. A knowledge base and an inference mechanism that drives this knowledge base to select from the rule base a generation rule corresponding to the operational status of the plant stored in the database to estimate the operational priority of the plant component equipment. An operation of determining and storing a recovery operation procedure for an auxiliary machine that was disconnected due to power supply switching control in the event of an accident based on the priority estimated by the equipment priority determination unit and the inference mechanism of the auxiliary equipment priority determination unit. The auxiliary equipment priority determination unit includes a procedure determination unit and an output device that outputs auxiliary equipment turn-on information in accordance with the operating procedure determined by the operation procedure determination unit, and the auxiliary equipment priority determination unit determines whether the power supply system Out of the plant operating state and input data stored in advance in the storage means when the plant is healthy, only the process opening is updated, inference is executed to estimate the priority of the auxiliary equipment, and the operation procedure determining unit according to this priority This system allows the system to determine recovery operation procedures.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of an auxiliary equipment recovery control device according to the present invention. In FIG. 1, 1 is an in-house plant at the LNGi site, and this in-house plant 1 is a detector that detects process quantities such as pressure and flow rate.

It consists of process equipment such as an in-house busbar, pumps, blowers, compressors, and piping. 2 also includes plant observation information (first input data) such as operation and stop status of each plant component when each N source system is healthy from the in-house plant 1, and process information 11 (second input data) controlled by plant auxiliary equipment. Input data) is taken in via the input device 3, and based on the plant operation status obtained from this, recovery operation information is outputted via the output device 4 in accordance with the priority of auxiliary equipment for plant operation, details of which will be described later. This is a digital meter.

In this case, the first input data transmission path connecting the in-house plant 1 and the input device 3 has a contact S that opens in the event of a power failure.
Therefore, when a power failure occurs, the first input data immediately before the failure is input to the digital paralysis meter 2 via the input device 3. This digital calculation-2 includes a memory unit 5 that temporarily stores the plant operation status based on the first input data from the in-house plant 1 in a healthy state, and a second input data, various constants, and the plant operation status stored in the memory unit 5. A knowledge base 6 consisting of a database that temporarily stores operational status, etc., a rule base that describes the relationship between the data stored in this database and the priority of auxiliary equipment as a generation rule, and a knowledge base 6 that drives this knowledge base 6 to Selects a generation rule corresponding to the stored data from the relationship between the stored data from the blunt stored in the rule base and the priority of the auxiliary equipment regarding this data, and outputs the priority of the auxiliary equipment according to the operational status of the plant. An inference mechanism 7, a storage unit 8 that stores line-up information of auxiliary units to be selected and cut off based on the priority of the auxiliary units outputted by the inference unit 7, and a priority level of each auxiliary unit stored in the storage unit 8. The sequence of restoration operations for disconnected auxiliary equipment is determined based on It is comprised of an operation procedure determiner 9 that performs grouping, determines operation procedures, and stores the results. Here, the knowledge base 6 and the inference mechanism 7 described above are the auxiliary machine priority determination unit 1.
It constitutes 0.

Next, the operation of the auxiliary equipment recovery control device configured as described above will be described with reference to the flowchart shown in FIG. FIG. 2 shows the procedure for obtaining recovery operation information for auxiliary equipment in the digital computer 2. First of all,
In step D1, it is determined whether or not a power supply fault has occurred, and if no power supply fault has occurred, step P1
The first input data and the second input data, which are current plant data, are taken in from the in-house plant 1 via the input device 3, and this plant data is input into the knowledge base 6.
database. In this case, the database of the knowledge base 6 stores not only plant data but also system fixed data such as various constants. Next step P2
The operational status of the plant is determined based on the input data using knowledge engineering methods, etc., and stored in the storage unit 5.
! i! Be prepared for the second battle. When the power supply is healthy and no power failure has occurred, the process ends.

Next, if a power failure occurs, YES in step D1.
The direction is selected and the process moves to step P11.

In step P11, only the process quantities, which are the second input data, are taken in via the input device 3, and only the process quantities stored in the database when the database was healthy are updated, and the process moves to step P3. In step P3, the inference mechanism 7 drives the knowledge base 6 to obtain input data stored in the database.

One of the corresponding generation rules is selected from among the auxiliary machine priorities described in the rule base of the knowledge base 6 based on the system fixed data and plant operation status, and roughly in step P4, the corresponding auxiliary machine 9 is selected according to the generation rule. For example, calculate the priority of seawater pumps. Next, in step 02, it is determined whether all the rules regarding the priority of each auxiliary device have been applied, and if there remain generation rules that are not applied, step P3. P4 selects and executes the generation rule. When all the generation rules regarding the priority of each auxiliary machine are applied in this way, the priority of each auxiliary machine is determined in step P5, and these priorities are stored in the storage unit 8 in step P6. Then, the operation procedure determiner 9 determines the order in which the disconnected auxiliary equipment is to be restored based on the priority of each auxiliary equipment stored in the storage unit 8, and the inrush of each bus determined from the power system configuration and plant operation status. Based on constraints determined by the current and process system configuration, auxiliary machines that can be restored at the same time are grouped, and the operating procedures are determined and stored. The output of the operation procedure determiner 9 is sent from the output device 4, and a recovery operation is performed on each of the forcibly disconnected auxiliary machines according to its recovery operation determination procedure.

Next, the recovery operation of the auxiliary machines by the above-mentioned auxiliary machine recovery control device will be explained in detail based on a specific example of a part of an in-house plant.

Figure 3 is LNGJ! ! This shows part of the local NG transmission system. In Figure 3, 11 is liquefied natural gas (LN).
13 is a BOG compressor that extracts the natural gas (NG) vaporized in the tank from the tank 11 and maintains the pressure in the tank 11 at a predetermined value. It is driven by a connected electric motor 1119. B
This is a suction drum for increasing the efficiency of OG compressed air 13. 15 also heats LNG with seawater and vaporizes it.
The RV vaporizer 14 is an LNG pump that supplies LNG in the tank 11 to the OVR vaporizer 15;
4 is driven by an electric motor 20 connected to an in-house power source. Reference numeral 16 denotes an ORV seawater pump that supplies seawater to the ORV vaporizer 15, and this ORV seawater pump 16 is driven by an electric motor 1121 connected to the in-house power supply. 17 is a suction drum 12 and an ORV vaporizer 15
A gas delivery pipe connected to a common gas output line with the base and the consumption value. 18 is this gas delivery pipe 1
This is a well installed on the base side of No. 7 to prevent backflow of gas in case of emergency.

In a plant with such a configuration, normally the tank 11
The NG generated inside the tank is supplied to the gas discharge pipe 17 via the suction drum 12 and the BOG compressor 13, and the LNG
Gas delivery pipe 17 via pump 14 and ORV vaporizer 15
NG is supplied to

In addition, at times of low load such as at night when the amount of gas sent from the base to the consumption area through the delivery pipe 17 is very small, the LNG pump 1
4. In some cases, the OVR seawater pump 16 and OR ■ vaporizer 15 are stopped, and the NG generated in the tank 11 is sufficient.

When a power failure occurs in such a plant, the motor connected to the faulty power bus will be switched to the healthy power bus, but the inrush current tolerance determined by the healthy system components In some cases, it may not be possible to switch all motors to the healthy bus at the same time. In this case, some electric motors are disconnected from the busbar, a so-called selective disconnection.

Here, consider a case where the electric motor 20 for the LNG pump 14 and the electric motor 19 for the BOG compressor 13 are disconnected from each other as a result of selective shutoff. If the plant operating state before the accident is not under low load, the amount of gas generated in the tank 11 is generally small compared to the amount of gas delivered.

So, is the electric T120 for LNG pump 14 BOG compression? ! It is necessary to perform the restoration operation earlier than the electric motor 19 for 113. On the other hand, when the plant operation status before the accident was low load with a small amount of gas sent out, the electric motor 19 for the BOG compressor 13
It is necessary to perform the restoration operation earlier than the electric motor 19 for the LNG pump 14. In addition, if the pressure in the tank 11, which is one of the various process quantities after an accident, increases, the BOG compressor 13
It is necessary to restore the electric motor 19 for use as soon as possible.

In this way, the selection criteria for operating procedures for auxiliary equipment that should be restored will change depending on the operational status of the plant when it is healthy, and
Post-accident pressure is the input data.

Naturally, the selection of auxiliary equipment to be selectively cut off also changes depending on various process quantities such as flow rate. For this reason, the priority of the auxiliary equipment to be operated is determined based on the process fillffi after the accident and the operational state of the plant before the accident, and the limit value of inrush current during recovery operations is determined from this priority and the plant components. For example, the operating procedures and grouping of auxiliary equipment to be restored are determined based on constraints determined from the configuration of the process system, such as the need to shift the timing of operation of OVR seawater pumps and LNG pumps.

Figure 4 is a flowchart showing an example of prioritizing the ORV water pump 16, which is one of the auxiliary machines in the plant configuration, using the confidence factor CF of the low load state, which is a part of the plant state. be.

It should be noted that the priority of auxiliary equipment has quite ambiguous elements, and it may not always be possible to make a definitive judgment, especially near the limits of the allowable inrush current. The purpose of this is to process the information to determine operating procedures and grouping.

Priority C of ORV seawater pump 16 with reference to FIG. 4 below.
The calculation of FO will be described. Introduction OVR seawater pump 1
Set the priority of 6 to CFO-0, and OVR seawater pump 1
6 was in operation before the accident, and if it was not in operation, CFII remains at O (that is, no recovery operation is required). Also, if you are driving, C.
Set po to a specified Ia, for example 0.4. Next, in the plant operation state before the accident, the confidence level Cp of the low load state is 0.
．． Check whether it is 9 or more. When Cp≧0.9 (that is, when there is a strong possibility of a low load state), Cva is 0.
．． 4, and when CF<0.9 (that is, when the low load condition is not strong), CFO is corrected to a predetermined value 1, for example 0.6. This can be concretely expressed using a known calculation formula for stochastic OR as shown in the following formula.

CFII - Cpa + Q, 6-0.6KCp.

Next, it is checked whether the confidence factor CF in the low load state is 0.5 or more. When Cp≧0.5 (that is, when there is a possibility of a low load state or when there is a strong possibility of a low load state)
is corrected by a predetermined value 1, for example 0.6. That is, Cps −Cpn +Q, 6−0.6”GCpn and
When CF<0.5 (that is, when there is no possibility of a low load state), Cpa maintains the same value.

In this way, if the ORV seawater pump 16 was in operation before the accident and Cp<0.5, that is, when there is no possibility of a low load state in the plant operation state before the accident, the priority is set to Cpa.
= 0.904, and if the ORV seawater pump 16 is in operation and 0,9 > Cp≧0.5 (that is, there is a possibility of a low load state), CFII = 0.76, ORV
When the dark water pump 16 is in operation and CF2O, 9 (that is, there is a strong possibility of a low load state), Cps = 0.4
．． While the ORV seawater pump 16 is stopped, C; Fcr-0.

As mentioned above, if the operation is not under low load, the priority of the 0RVi water pump 16 is set high to speed up the recovery operation.
Also, as the load gets closer to the low load state, ORV seawater pump 1
Lower the priority of 6 and put other 1, for example BOG compressor 13
It is possible to perform control such that recovery is given priority.

This is possible to some extent with conventional computer control, but since the inference structure and knowledge base are structurally integrated, the program becomes more complex as the system becomes more advanced.

In this way, when determining the priority of auxiliary equipment based on the plant operation status, the knowledge base 6 and the reasoning mechanism 7 are separated and processed in a knowledge engineering manner, so the plant operation status is reflected in detail in the form of rules. This enables a variety of control.

In addition, determining the priority of auxiliary equipment conventionally required a program with a complex algorithm and was fixed, but in this embodiment, only a knowledge base based on rule descriptions is used, so the contents of the program can be easily read. can. Therefore, even a person other than the program creator can easily read the program if the inference mechanism is unified, and in turn, the system configuration can be easily modified or changed.

〔Effect of the invention〕

As described above, according to the present invention, the process is controlled by the first input data, which is plant information such as the operation and stop status of each plant component device when each power supply system is healthy, and the plant auxiliary equipment after an accident. Second input data, which is various quantities, are taken in, and the pre-accident plant operation status obtained from this second input data and the first input data is stored in a knowledge base database, and the knowledge base is inferred. Driven by a mechanism, a generation rule corresponding to the second input data, the plant operation status, and the operation status of the plant stored in the rule base of the knowledge base as a generation rule in advance is selected, and priority is given to the operation of the plant component equipment. Estimate the degree and reason this! Based on the priority estimated by the system, the recovery operation procedure for the auxiliary equipment that was forcibly disconnected when the power supply system failed is determined, and the operation procedure information is output.
Restoration operations can be controlled in detail and efficiently.
Moreover, it is possible to provide an auxiliary equipment recovery control device that requires less labor than one hour for depacking.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the auxiliary recovery control II device according to the present invention, FIG. 2 is a flowchart for explaining the operation of the embodiment, and FIG. 3 is a detailed diagram of an in-house plant. System configuration diagram showing an LNG terminal as an example, No. 4
This figure is a flowchart showing a procedure for estimating a low load state by the apparatus of this embodiment in the in-house plant of FIG. 3. 1...In-house plant, 2...Digital computer, 3...Input device, 4...Output device, 5...Storage unit, 6...Knowledge base, 7...Inference mechanism, 8...Storage unit, 9...Operation procedure determiner, 10...Supplementary information Machine priority determination section. Applicant's agent Patent attorney Takehiko Suzue 125W Figure 3

Claims (1)

[Claims] If there are multiple buses that receive power separately from different power supply systems, and one of the power supply systems fails, the faulty power supply system is disconnected from the faulty power system's bus, and a busbar connection breaker is turned on to connect the faulty system's bus to the other bus. In an auxiliary equipment control device that operates plant component equipment by receiving power in parallel from the healthy side bus of the power supply system, the operation/stop state of each plant component equipment is controlled by the plant auxiliary equipment when each power supply system is healthy. an input device that takes in plant observation information such as various process quantities taken in as input data; a storage means that temporarily stores the operating state of the plant obtained from the input data taken in by the input device together with the input data; A knowledge base consisting of a database in which the operating status of the plant and input data stored in the means are accumulated together with fixed data such as various constants, and a rule base in which various information regarding the operational priorities of the plant component equipment is accumulated in advance as generation rules. and an auxiliary equipment priority system comprising an inference mechanism that drives this knowledge base, selects from the rule base a generation rule corresponding to the operational status of the plant stored in the database, and estimates the operational priority of the plant component equipment. and an operation procedure judgment that determines and stores the recovery operation procedure for the auxiliary equipment that was disconnected due to power supply switching control in the event of an accident based on the priority estimated by the inference mechanism of the auxiliary equipment priority determination unit. and an output device that outputs auxiliary equipment turn-on information in accordance with the operating procedure determined by the operating procedure determining unit, and the auxiliary equipment priority determining unit determines the above information in advance when the power supply system is healthy after switching the power supply in the event of an accident. Of the plant operation status and input data stored in the storage means, only the process quantities are updated, inference is executed to estimate the priority of the auxiliary equipment, and the operation procedure determining unit is informed of the priority according to this priority. An auxiliary equipment recovery control device characterized in that a recovery operation procedure is determined.