CN1226732A - Pump selection logic - Google Patents

Abstract

The operator of a nuclear steam supply system manually selects a lineup of either one, two, or three main feedwater pumps for normal reactor operation to generate power. A system (RPCS) for implementing a step reduction in the power output of the reactor, includes an associated logic circuit which combines signals indicative of tripping of one or more pumps, with the pump status latches, to achieve the following outcomes: (a) with one pump selected, a trip of this one pump does not produce an RPCS trip demand signal (because the reactor will be tripped); (b) with two pumps selected, (i) a trip of one pump will produce an RPCS trip demand signal, whereas (ii) a trip of these two pumps will not produce an RPCS trip demand signal; (c) with three pumps selected, (i) a trip of one pump will not produce an RPCS trip demand signal (because the transient can be handled by the basic control system), (ii) a trip of two pumps will produce an RPCS trip demand signal, and (iii) a trip of three pumps will not produce an RPCS trip demand signal.

Description

Pump selection logic

The present invention is September 30, 1996 filed a patent application continue No.08/724081 Continued application.

The present invention relates to nuclear power plants, and more particularly, relates to nuclear reactor control system to sudden , No unexpected damage to the main plant components feature an automatic response.

Pressurized water nuclear power plant nuclear steam supply system (NSSS), and flow fluctuations of the energy normally very Small environment. In this case the reactor by the basic process control system. However, There will be some large equipment imbalances, such as large turbine load barriers, turbines or partial interruption Loss of main feedwater pump supply line capacity. In this case, higher than the conventional Speed ​​control rod insertion much faster, rapid decrease NSSS energy and will NSSS system maintenance Held in the control range. In addition, rapid NSSS energy reduction can be made without interruption reactor The case of the thermal margin sufficient to adjust the internal control rod deviation (including false rod Whereabouts).

To achieve this goal a known system is available from the U.S. city of Windsor , Conn. (Connecticut, Windsor) for Combustion Engineering (ComBustion Engineering, Inc) to buy To reduce system energy reactors (ReActor Power CutBAck System, RPCS). Promulgate Cloth on February 21, 1978 U.S. Patent No. 4,075,059 , "reactor can Reduction system and method "describes such RPCS. Hereby with the contents of the disclosure As a reference. The system is designed for large-scale load fault , the loss of a feed pump or rod internal Deviations ( including false rod drop ) is designed to provide a gradual reduction of energy reactors Less . Reactor energy progressively reduced through efforts to adjust the control rods into the reactor core One or more groups pre- set to achieve while falling . These control rods to their usual Insertion order whereabouts . The RPCS also began to reduce energy from the reactor to the turbines A control signal to restore energy balance turbine and reactor , and the steam generating device Water level and pressure are restored to their normal control values.

There are two traditional NSSS steam generating unit and two variable speed main feed pumps , water supply Pump is piped to the public secondary cooling water, cooling water by the respective threshold door distribution and control to send to each A steam generating device . In the event of a steam generator feed water pump failure , sent to the steam generator Means of the secondary cooling water flow is reduced , because the pump can not supply the remaining steam generating means To 100% of the feedwater . When this occurs , the steam generating device continues to water ( the water Into steam ) than the fast water into the steam generating device , thereby causing the water level in the steam generating device Decreased . In the reactor and turbine steam generating device instructed the signal level is too low to be Circuit does not allow this situation before too long . If the reactor immediately rapid reduction of energy To the full extent , and the steam generating device to generate steam capacity is also reduced , thus avoiding Due to the low steam generator water level caused by the reactor turbine trip . In general, for each nuclear power plant A steam generator with water flow capacity with a total of 65% of the two feed pumps, in order to avoid Reactor interruption and loss of energy required to pump the initial reduction of the total energy reactor 75% . This allowed the loss of a reactor feed pump continues to run after the restrictions energy By the system pump capacity and steam generating device characteristics of the decision .

For power plants starting from the plant operator to manually start the feed pump, or through the turbine Driver supply steam and cooling water, or to power the electric drive. Pump from a reservoir or cold Condensate reservoir and pumping the water to the reservoirs or condensate is recycled to the reservoir. When the pump is started, and Check the operating normally, its speed set by the operator at the minimum control speed. When the plant status Yung Xu one or two feed pump switch to the automatic control of the feedwater control system, the operator will be selected With the pump control switch to automatic mode. In automatic control, the feedwater control system sets Pump speed, and control the valve position to maintain the predetermined level the steam generating device.

In these plants, the feed pump and the RPCS in the following ways:

Energy levels	Water station status	RPCS Status	Operator behavior	Plant response
					0 to 50%	A feed pump is energized (To run speed for Water to the steam generating device Set), and the second pump	Do not use	Rose 5% in the energy Before the above, the water supply The control system is self- Action. This controls the feed pump	If the running Feed pump off Road, because the steam Generator water

	Or energized but in Standby (with a minimum follow Loop speed rotation, not Water to the steam generator Device) or off Electricity, stop using it.		To run speed rpm Action. In the energy down to 5% or less, will Water control in hand Action.	Bit is low, the starter Reactor trip Devices.
					50-100％	Two feed pump is energized And running speed for Water	Use	In about 50% of the energy (Increase), the second To the pump from the control room Set in the automatic control The system. RPCS in Two feed pumps in Automatic control is Use.	If one of the A feed pump off Road through RPCS circuit life Start command signal Melon can move in a heap Reduction system Systems.

This makes it necessary to NSSS offers three main feed pumps; third is used to pump Standby equipment or to run with the other two sharing. Orders can be easily RPCS Coupled to a main feed pump NSSS three configurations, the present inventors have conceived The improvement of this RPCS logic, which uses three pumps NSSS provided greater operational Flexibility.

Accordingly, an object of the present invention is to have at least three main feedwater pump NSSS offers Improved RPCS logic.

A further object is automatically generated when the RPCS command signal, RPCS logic 2 Pump pump pump pump and three distinguished.

According to the present invention, NSSS operator to manually select 1, 2 or 3 primary water Pump pumps normal reactor operation for power generation. This option sets the status of each pump latch Device or to reset it, represents the expected operation of the pump. A logic circuit to indicate that one or more pumps Circuit pump status signals and said latch connection, in order to achieve the following results:

(A) has a pump is selected, the pump does not produce an open circuit RPCS command signal (because The reactor will be disconnected, for example, when the steam generator water level is low).

(B) are selected with two pumps, (ⅰ) RPCS a pump circuit will generate a command signal circuit, and (Ⅱ) two pump circuit breaker will not produce RPCS command signal.

(c) the three pump is selected, (ⅰ) will not generate a pump circuit disconnection RPCS command signal (because This transient state can be the basic process control system), (ⅱ) circuit will produce two pumps off RPCS Road command signal, and (ⅲ) three pump circuit RPCS command signal is not generated.

This logic is best determined by redundancy and sub-logic implementation. For example, each of the feed pump circuit Produce two separate feed pump trip signal. Similarly, each state choose to start two pumps Different status latches. Those pump circuit signal and pump status latch logic gates in a separate Matching the array, so that operation of the pump of choice of a specific pump circuit, resulting in redundant I RPCS circuit control signal. However, the RPCS not to be open circuit, unless said one The two logic gate array logic gate circuit are generated by the control signal recognized RPCS.

The method of the invention can be integrated for nuclear power plants, the latter comprising: a reactor; at least three A water supply to the steam generator feedwater pump; energy output of the reactor core control rods System; well as the loss of at least one feed pump to the reactor core operation quickly insert some Controlling holding to the original level of the energy output from a non-zero level of the system is reduced. This method is the root Selected by the operator, according to which a pump will be used to pump water supply operation and which one to go from the water supply operation Lost to the system results in a rapid control rod insertion portion command signals. Each intended for water supply Operated pump losing water to produce a trip signal operations are. Only when, in addition to a selected pump All pumps are an outside signal generating circuit only when booting the system quickly produce some control rods Insert command signal.

Figure 1 is a nuclear steam supply system, energy reduction reactor system functional logic diagram; and

Figure 2 is a preferred embodiment of the present invention, due to the loss of three main feed pumps to one or A plurality of, energy cut command signal generating reactor circuit logic diagram.

Figure 1 schematically illustrates the energy cut of said reactor system (RPCS) 12 related functions Figure 10 can take part. The reactor system encounters a transient reduction in energy to the control rod drive Mechanism 14 sends a control signal, and with the turbine control system 16 match, the NSSS The energy stability after a reduction, but non-zero levels. If RPCS can not make Turbines running slow and regulate the NSSS control rod group is stable, RPCS disconnect a group or Groups of control rods.

The present invention, in block 18 by the command system interrupt generation reactor life energy cut Command signal in the case, there is a mechanism associated logic, be used in place RPCS12 Management. For example, the function block 12 in the processing of selection criteria, including the control rod 20, and its the Body are also dependent on plant NSSS data provided by the sensor 22. To calculate the NSSS other Conditions by the function block 24 to provide RPCS12. RPCS is also subject to the reactor operator Reduction control of the control panel 26, an alarm is generated by RPCS12 displayed on the operation control Part of the alarm stage 28.

Figure 2 shows the A, B, C three main feed pumps pump selection logic 100. That Circuit functions can be divided into four parts: (1) selection and start the pump section 102; (2) to the pump circuit Signal section 104; (3) logic implementation section 106; and (4) RPCS break command section 18. Figure 2, the function of the command section 18, the present invention has been described in terms of Figure 1 can be considered the Module 18 has the same function.

Section 102 for each of the main feed pump A, B and C have at least one switch 108, And preferably further has at least one switch 110, the operator can use it to select that particular pump In the case of normal power generation plant whether to full load. When running at full capacity, pump speed control For example, by more than 5% power plant automatic feedwater control system (not shown) is adjusted automatically. When the Is not running at full capacity, the pump or electricity but is on standby, or off, stop Be used. Thus, the operator can specify which automatically controls the pump from running intention to withdraw. Automatic water supply control system to control the pump speed variation and the threshold door position to keep the steam generating device Predetermined level. Although not in the NSSS run properly, run the pump can operate In fact, by the manual control is in the "standby" state, and thus the pump corresponding to the production of other pumps Steam generating apparatus raw minimum recirculation flow speed.

In the illustrated embodiment, the main feed pump A has a switch 108A, which is located in electrical Station control room, for example, with the main control panel or system linked to the pump motor control Heart, can pull to manually start or stop position. The "start" position that corresponds to the selected Status: Pump to operate at full capacity. "Stop" position means exit from the full-load operation, Or "off" or in standby. As used below, "run" means "running at full capacity." Each switch 108A and 110A spread one pair of logic condition a logic "or" gate 112A, 114A , They output the incoming trigger circuit 116A. Line 118A the output of the circuit 116A Of Q, when the operator selected the switch 108A or 110A pump A start condition, it Is a logic "1." This logic "1" to "and" gate 120A, which starts from the latch The role of the state indicates that this particular pump is available for operation.

It should be noted that each of the main feed pumps B and C are associated switches 108B and C; 110B And C; 112B and C; 114B and C; 116B and C; 118B and C; well as 120B And C, which is very important.

Preferably said state latches have redundancy, so 118A, 118B and 118C output A logical condition will pass to their respective second "and" gate 122A, 122B, and 122C. This Kind, as an example, if the operator through manual selection switch 108A or 110A main feed pumps A START condition, then the latches 120A and 122A are redundant manner will be activated.

Said trip signal to the pump portion 104, respectively, including the three 124A, 124B, and 124C represents the main feed pump A, B and C, each of the control plane from the main Plates, such as 126A, B, and C, and 128 as shown by one or more water The control system to respond to the input signal. Feedwater control system 128 and generate a trip signal Associated control logic is not part of the invention. However, it is worth mentioning that, for such 124A For each pump, the pump circuit breaker would result in two signals 130A, 132A, are each Spontaneously to latch 120A and 122A in. Similarly, the trip signal 130B, 132B And 130C, 132C respective spread latches 120B, 122B and 120C, 122C medium. When any one particular door latch 120A, B, C or 122A, B, C inputs Are logic "1", the respective lines 134A, B or C, or 136A, B or C On a corresponding logic "1" output signal. ...

Said trip signal to the pump portion 104, respectively, including the three 124A, 124B, and 124C represents the main feed pump A, B and C, each of the control plane from the main Plates, such as 126A, B, and C, and 128 as shown by one or more water The control system to respond to the input signal. Feedwater control system 128 and generate a trip signal Associated control logic is not part of the invention. However, it is worth mentioning that, for such 124A For each pump, the pump circuit breaker would result in two signals 130A, 132A, are each Spontaneously to latch 120A and 122A in. Similarly, the trip signal 130B, 132B And 130C, 132C respective spread latches 120B, 122B and 120C, 122C medium. When any one particular door latch 120A, B, C or 122A, B, C inputs Are logic "1", the respective lines 134A, B or C, or 136A, B or C On a corresponding logic "1" output signal. ...

"Or" gate 138 receives data from three 146, 148 and 150 "and" gate signals. If three "and" gate generating any logic "1" output, "or" gate 138 That generates a control signal on line 142. Similarly, as part of the redundancy, such as If the "gate" 152, 154, or 156 in any one of the output to a logic "1", the "or" Gate 140 will pass on line 144 circuit control signal. If and only if the response two different pump conditions The signal has a logic "1" input of the "and" door, "and" gates 146-156 Each of the generated logic "1" output signal.

It is noteworthy that the present invention can be very clearly distinguish three feed pumps, only two An available operating conditions, and are available for all three feed pump operating conditions. "Or" gate 160-182 on the "and" gate array between 120, 122 and 146-182 play case If the pump is operable in only one of the two circuit, the circuit generates a command signal RPCS; the Three pumps only one circuit is operable, the inhibition command signal generating circuit role. Large Body, the need for two of the three pump disconnection case, the "AND" gate 146-156 only To "or" gate 138, 140, transfer logic "1" signal. For example, if the main feed pump A Not operate equipment such as standby equipment, etc., which are available for operation with three pumps Configuration is considered equivalent to the circuit of the pump. Thus, the switch 108A, 110A are in the stop Case, the line 158A on the output signal of flip-flop Q-116A is a logic "1." In this case, the output signal Q is a logic 0, and thus does not start gate 120A. However, In order to achieve one of B or C, when the pump circuit, the line 142 (and line 144) to generate the desired off Channel control signal, the logic portion 106 such that the output must be generated, it pumps in all three A, B and C are available for operation of the pump during operation of the station A and B in the case logic circuit Generated logic section 106 outputs the same. Thus, the Q-output of flip-flop logic 116A "1" to the "or" gate 160, so that the logic "1" can be transferred to "and" gate 146. If, for example in the pump circuit B, "and" gate 120B through the "or" gate 162 Logic "1" transmitted to "and" gate 146, "and" gate 146 will logic "1" spread "or" Gate 138, and spread through the command line 142 part 18. ...

It is noteworthy that the present invention can be very clearly distinguish three feed pumps, only two An available operating conditions, and are available for all three feed pump operating conditions. "Or" gate 160-182 on the "and" gate array between 120, 122 and 146-182 play case If the pump is operable in only one of the two circuit, the circuit generates a command signal RPCS; the Three pumps only one circuit is operable, the inhibition command signal generating circuit role. Large Body, the need for two of the three pump disconnection case, the "AND" gate 146-156 only To "or" gate 138, 140, transfer logic "1" signal. For example, if the main feed pump A Not operate equipment such as standby equipment, etc., which are available for operation with three pumps Configuration is considered equivalent to the circuit of the pump. Thus, the switch 108A, 110A are in the stop Case, the line 158A on the output signal of flip-flop Q-116A is a logic "1." In this case, the output signal Q is a logic 0, and thus does not start gate 120A. However, In order to achieve one of B or C, when the pump circuit, the line 142 (and line 144) to generate the desired off Channel control signal, the logic portion 106 such that the output must be generated, it pumps in all three A, B and C are available for operation of the pump during operation of the station A and B in the case logic circuit Generated logic section 106 outputs the same. Thus, the Q-output of flip-flop logic 116A "1" to the "or" gate 160, so that the logic "1" can be transferred to "and" gate 146. If, for example in the pump circuit B, "and" gate 120B through the "or" gate 162 Logic "1" transmitted to "and" gate 146, "and" gate 146 will logic "1" spread "or" Gate 138, and spread through the command line 142 part 18. ...

It should also be pointed out that if the pump can run simultaneously shown circuit, gate 138 or 140 are not to RPCS command section 18 transfer circuit breaker control signals. In this case, since the RPCS 12 action, the reactor water level is low in the steam generating device and the all cut off, the energy fission Reduced to zero, rather than simply be reduced to a lower energy non-zero value.

Having three NSSS main feed pumps, each pump to provide the required steam generating device Water 33.3%, but the maximum capacity of each pump water for at least 50%. The counter of the present invention Energy cut the reactor system is best to use the following way:

Energy Level	State of water supply	RPCS Status	Operator behavior	Plant response
					0 to 40 %	A feed pump through Electricity (to run faster Water to the steam generator Raw device); second Pumps powered up, but at the In standby mode (to Minimum speed transport OK, do not water to the steam Steam generating means); The third pump off Electricity.	Do not use	In the energy rises to 5 % Prior to water Control system in a self- Dynamic way. Operator Through the pump selection logic Select the pump is running Or standby state.	If running to the pump Circuit may cause electric Stand off.
40％	Two feed pumps through	In about 50%	About 40% of the energy	If in running speed

To 70 %	Power-up to operating speed From the water, the third pump Powered in standby State.	To 60% energy Volume level Getting Started	, The second feed pump Start using. Operating Control in the water supply system Select the transport control panel The line pump, the selection Select from the RPCS logic Series identification.	A feed pump off Road, water supply control system The second run will be increased to Pump speed. According to Original energy level, RPCS interrupt will be generated Command signal, by the following Rod drop quickly to reduce energy Volume, the energy reduction, And to turn a turbine Less Slow. If the two feed pumps Open circuit, reactors, steam Steam generator water level is low Will be cut off. ...
					A feed pump off Road, water supply control system The second run will be increased to Pump speed. According to Original energy level, RPCS interrupt will be generated Command signal, by the following Rod drop quickly to reduce energy Volume, the energy reduction, And to turn a turbine Less Slow. If the two feed pumps Open circuit, reactors, steam Steam generator water level is low Will be cut off. ...	Two feed pumps through Power, the third pump off Electricity, do not use	In about 50% To 60% energy Volume level Getting Started	About 40% of the energy , The second feed pump Start using. Operating Control in the water supply system Select the transport control panel Line pumps. The selection Select from the RPCS logic Series identification.	If a pump circuit, RPCS will produce RPCS interrupt command signal Number. If two water supply Pump circuit, power plants will cut Broken.
70% To 100 %	Three pumps are through Power-up to operating speed The water supply.	Use	In a third to 70% Pumps started, And this by the RPCS Select the logical identifier.	If a pump circuit, The other two pumps compensate third Pump to lose. If the loss of To two pumps, RPCS RPCS command generates an interrupt Command signal.

Can be seen from the above description, only if at least two full-load operation, and to pump water Control system is in automatic mode RPCS began to be used. Traditional RPCS in the reactor At least 50% of energy (50% -60%), and the feedwater control system is in automatic mode until the time Finally in use. At least 50% of the energy feedwater control system is always powered. Reaction Reactor feedwater control system and the energy cut relationship between systems in several ways. RPCS preferably from the feedwater control system to automatically detect (without operator involvement) which the pump is to be Operation. Therefore, the choice which the pump is to be run, and specify which pumps the exit from the pump operation Switching means may be an operator control panel used in the pump is in use on the same switch Devices. When the energy level exceeds 50%, and when you start using the RPCS, RPCS "read out" Originally selected by the operator of the pump state. Or, RPCS may be designed such that, when energy Levels increase the amount of more than about 50%, started using RPCS, the operator through RPCS professionals Switch to manually select which feed pump to be run. ...

Can be seen from the above description, only if at least two full-load operation, and to pump water Control system is in automatic mode RPCS began to be used. Traditional RPCS in the reactor At least 50% of energy (50% -60%), and the feedwater control system is in automatic mode until the time Finally in use. At least 50% of the energy feedwater control system is always powered. Reaction Reactor feedwater control system and the energy cut relationship between systems in several ways. RPCS preferably from the feedwater control system to automatically detect (without operator involvement) which the pump is to be Operation. Therefore, the choice which the pump is to be run, and specify which pumps the exit from the pump operation Switching means may be an operator control panel used in the pump is in use on the same switch Devices. When the energy level exceeds 50%, and when you start using the RPCS, RPCS "read out" Originally selected by the operator of the pump state. Or, RPCS may be designed such that, when energy Levels increase the amount of more than about 50%, started using RPCS, the operator through RPCS professionals Switch to manually select which feed pump to be run. ...

Claims (5)

1. In a pressurized water nuclear reactor in a nuclear counter, the at least one steam generator, the steam generator Certain raw device to pump water through the normal speed control rod insertion Reactor First system core energy output, and including faster than said normal speed of some Reactor core rod insertion device to the second system, which occurred at a pump running so Impaired energy output will be reduced from the original value to a nonzero value, wherein said steam generating equipment Set with three feed pump station improvements include the following:

% E7% 94% A8% E4% BA% 8E% E6% 89% 8B% E5% 8A% A8% E9% 80% 89% E6% 8B% A9% E4% B8% 89% E6% B3% B5% E4 % B8% AD% E5% 93% AA% E4% BA% 9B% E6% B3% B5% E5% B0% 86% E7% 94% A8% E4% BA% 8E% E4% BE% 9B% E6% B0 % B4% E8% BF% 90% E8% A1% 8C% E5% 92% 8C% E6% 8C% 87% E5% AE% 9A% E4% B8% 89% E6% B3% B5% E4% B8% AD % E5% 93% AA% E4% BA% 9B% 0A% 20% 20% 20% 20% 20% 20% 20% 20% 20% 20% 20% 20% 20% 20% 20% 20% E6% B3 % B5 (% E8% 8B% A5% E6% 9C% 89% E7% 9A% 84% E8% AF% 9D)% E4% BB% 8E% E4% BE% 9B% E6% B0% B4% E8% BF % 90% E8% A1% 8C% E4% B8% AD% E5% 8E% BB% E6% 8E% 89% E7% 9A% 84% E5% BC% 80% E5% 85% B3% E8% A3% 85 % E7% BD% AE% EF% BC% 9B

When intended for running water pumps are essentially unable to carry out a particular water supply, from the pre- Be used to run separately for each pump signal generating circuit pump means;

In said second switching system, said pump means and said trip signal generating means Responsive device for only in the following circumstances generate a command signal to quickly insert Into a number of control rods:

When two pumps has been selected, only from the selected one of the pump of the pump signal generating circuit pump Number, or

When three pumps has been selected, the pump only from the selected but not all, any two of the three Each pump generates pump circuit signals.

2. The nuclear power plant according to claim 1, wherein in response to said switching means and generating Pump trip signal means includes:

With each of said switching means associated pump trigger circuit, respectively, for when the pump is Selected in the first line to generate a first signal or, if the pump has been removed, in the second line Generating a second signal path,

Start "and" gate circuit, respectively, and said trigger means in each of said first Line is electrically connected, and, respectively, with the pump off the signal generating means is electrically connected, for example, only when The first signal and the pump trip signal overlap, each startup "and" gate before transmission logic "1" Output signal, and

Respectively, each of said start 'and' gate output terminal and electrically connected to said second line "Or" gates.

3. The nuclear power plant according to claim 2, wherein responsive to said switching means and generating Pump trip signal means includes:

A pump for the possible combinations of the two pumps in each of the logical "and" Doors, each logical "AND" gate in response to a pump connected to the second line of the "or" A gate output signal in response to said pump, and the other of the second line connection Said pick "or" gate the output signal of another.

4. In a pressurized water reactor nuclear power plant, at least two steam generating device, the steam The three generating device to pump water through the normal speed while the control rod insertion reaction Reactor core energy output first system, and including faster than said normal speed Some of the reactor core rod insertion device according to a system which at least one of the water Failure of the pump is running when the energy output from the original value was reduced to a non-zero value, wherein Generate a command signal for the second system quickly insert the control rod comprises the following steps of:

Set for the pump manually select which of three water pumps will be used to run and specifies three pumps Which pump (if any) are removed from the water supply operation of the switching device;

From intended for water supply operation, and essentially unable to carry water to produce each pump Pump circuit signal;

Response switching device settings and pump trip signal, and only in the following cases only for the second series System generates command signals to quickly insert some rods:

(a) selecting a pump is running, which can be selected in case the pump circuit does not generate a command Signal,

(b) two pump operation is selected, only one is selected in case the pump circuit, generation command Signal, and

(c) three pump operation is selected, only the selected pump circuit two cases, generation command Signal.

5. The method claimed in claim 4, characterized in that:

The step of generating a command signal having a pump associated with each pump of the logic state of the latch For series circuits, each latch status indicates whether or not a predetermined supply of each pump operation, in order to And

Setting switches the latch step produces a start-up state, and thus from the respective Pump trip signal may pass through the logic circuit.