JPS6041531B2 - How to monitor power units operated in parallel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for monitoring and controlling at least three sets of power units that are operated in parallel and each output power is directed to a common load.

The term "power unit" is used here for any type of device that generates or transmits electrical or mechanical power.

Power units can therefore include, for example, generator sets, power transmission equipment, converters, transformers, diesel generator sets, turbine banks, electrical or mechanical drive motors, torque transformers, turbine and marine propeller drives, and also all types of power units. pneumatic, hydraulic and mechanical devices are meant. The term "power unit" does not include control and regulation technology devices for signal processing purposes. The arrangement of multiple sets of power units that are operated in parallel is generally done to increase the operational reliability of the load.

If any unit fails, the remaining units will take over power supply to the load. However, there are problems in monitoring multiple sets of units of approximately the same capacity that are operated in parallel. This is because failures that do not completely degrade any unit are difficult to identify using normal monitoring methods. Monitoring the operating characteristic parameters of each power unit as to whether predetermined limit values have been exceeded is made difficult by the fact that the individual units are not operated with their full power output in non-fault operating conditions. When forming the value of the difference between the same type of operating characteristic parameters in each two sets of power units,
It is not possible to determine with certainty which unit has failed. This problem will be explained in more detail using a simple example.

Now, it is assumed that the load is supplied with power via the bus from three sets of inverters with the same configuration as power units, and that two of the three sets of inverters can work together to supply the required load power to the maximum amount. . In the event of a failure that results in a reduction in the output power of any of the inverters, the operating characteristic parameters, such as the output current, of none of the three inverters will exceed predetermined limits. Therefore, the failure may not be discovered and may develop into a secondary failure. Even if a large number of operating characteristic parameters are monitored in the information unit or conversion unit of the inverter, failures cannot be reliably detected in all operating conditions. On top of that,
It is also conceivable that a fault in one of the inverters causes the output current of the non-faulty inverter to exceed a predetermined limit value, thereby causing the non-faulty inverter to be shut off. By forming the value of the difference between the output currents of each two sets of inverters, it can be established that a fault exists. However, it is not possible to determine which inverter has failed. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an easily implemented method for monitoring and controlling a plurality of sets of power units operated in parallel, such that faulty units can be unambiguously identified and shut down.

Such an objective is achieved according to the invention by providing at least three sets of power units operated in parallel and each output power directed to a common load, each power unit being provided with measurements of the same type of operating characteristic parameters. A detector for detecting, a cutting device for cutting off the power unit, and a monitoring device are attached, and each monitoring device has at least two sets of measured values of operating characteristic parameters of the power unit to which each monitoring device belongs. each measurement value of the operating signature/parameter of the other power unit is introduced and has the function of respectively comparing the measurement value of the former with at least two measurement values of the latter, and each monitoring device When a difference exceeding a predetermined response value occurs between the former measured value and at least two of the latter measured values, a cutting device belonging to the monitoring device in which the former measured value is installed This is achieved by activating the monitoring device and controlling the power unit to which the monitoring device belongs.

In the present invention, the monitoring circuit is constructed based on m-out-of-n selection circuit technology.

m-out-of-n selection circuits, particularly 2-out-of-3 selection circuits, are known in the regulation art. Known devices for monitoring the functioning of individual control lines in analog multi-channel control systems with 2-out-of-3 selection circuits constantly compare the individual control lines with each other and prevent faults in the event of a fault in the control line. (German Patent Application No. 202094).

All adjustment lines are lead-backed to the input of the averaging circuit. Each of the two adjustment lines is connected to a three-point switch, which disconnects the adjustment line from the input of the averaging circuit and drives a switching device to simultaneously change the magnitude of its output signal or any input signal still present. do. An advantageous field of application for selection circuits of this type is the operational monitoring of research and power reactors (H&B-Sonderheft “IN
TERKAMA” Vol. 60, pp. 49-52).

The neutron flow in a nuclear reactor is an operating characteristic parameter,
It is detected by three ionization chambers as mutually independent detectors. The measured values of the three ionization chambers are combined in a mean value amplifier.

Furthermore, the measured values of the two ionization chambers are fed to a magnetic comparison amplifier which has a jump characteristic and predetermines the maximum permissible error value. When one measurement value is found to have an unacceptable deviation from the other two measurements,
The relay matrix isolates the faulty detector and switches the amplification of the mean value amplifier, thereby ensuring that the mean value is more correctly indicated.

Other applications of the aforementioned selection circuits are for redundant aviation control equipment, in particular for aircraft with vertical take-off and landing (DE 1277677), as safety circuits for regulating equipment and for synchronization control systems. As BB
C-Nachrichten” June 1961 issue, No. 3
pages 56-361), and even as a safety system in automatic process control ("elektrotechni
51, No. 14, July 23, 1969, pages 10, 11, 21).

All known applications of selection circuits of this type are such that a single object is monitored by several detectors, the measured values of which are processed redundantly in several adjustment channels, and the insertion of the selection circuit is solely for the adjustment. and in the direct area of control technology.

In contrast to this known application of selection circuits in regulation and control technology, the invention provides for the insertion of such selection circuits for monitoring several power units operated in parallel.

For this purpose, the known monitoring principles are modified accordingly. Each power unit is associated with a detector for monitoring operating characteristic parameters. The selection of suitable operating characteristic parameters and detectors depends on the type of power unit to be monitored. For example, electrical energy generation, transmission and conversion devices involve current or voltage values; mechanical, pneumatic or hydraulic power units involve other physical quantities such as temperature, pressure, flow rate, torque or torsion. become. No average values are formed from the measured values of the operating characteristic parameters. Instead, each power unit is associated with a shearing device that moves on each monitoring device. The type of device for disconnecting the power unit is again determined depending on the type of power unit; for example, an electric switch, a shut-off valve, a throttle valve, or a device suitable for disconnecting the respective power unit is provided. The selection circuit can be implemented electronically in a known manner.

However, it is also possible for this selection circuit to consist of pneumatic or hydraulic elements, provided that the necessary differential circuits, limit value indicators and band circuits are designed accordingly.
The present invention allows selective monitoring of multiple power units operating in parallel and of approximately the same power serving a common load or loads.

It is guaranteed that a failure in any power unit can be immediately determined even in a partial load region, and only the failed power unit can be shut off. For monitoring installations with three sets of power units operating in parallel, according to the invention each of the three sets of power units is provided with a detector, and the measured values of these detectors are led to a 2-out-of-3 selection circuit.

This case of operation requires no further explanation. This is because the measurements from the three sets of detectors can be processed by a selection circuit in a known manner. In a facility equipped with two sets of power units operated in parallel, insertion of a 2-out-of-3 selection circuit is not possible as is.

Therefore, according to the configuration of the present invention, both power units are additionally provided with a model unit or a simulator that simulates the behavior of at least one operating characteristic parameter of the power units, and both power units and the model unit or simulator are provided with a A detector is attached to each, and the measured value is led to a 2-out-of-3 selection circuit. The target model unit is a unit that has the same structure as the affiliated power unit, but is made with appropriately reduced components. The model unit therefore produces a power that is less by the proportionality constant. In that case, the detector attached to the model unit supplies a measurement value with a suitable proportionality constant, which measurement value is processed in the selection circuit together with the measurement value derived from the detector of the additional converter power unit. It is best to choose as follows. The power unit simulator is a device that simulates the behavior of at least one operating characteristic parameter of the power unit to be simulated by electronic, mechanical, pneumatic or hydraulic means.

Optionally, associated detectors can also be integrated into this type of simulator. The simulation device may be configured such that the value of the simulated operating characteristic parameter can be processed in the selection circuit with the measured value of the detector of the power unit. For monitoring installations with four or more power units, the invention has various embodiments.

The simplest embodiment is for a selection circuit associated with each power unit to be provided with measured values of the operating characteristic parameters of the associated power unit and of the other two sets of power units. In that case, if one of the power units fails, the supervisory control device will no longer function. This embodiment is therefore suitable for installations where failure of more than one set of power units is highly unlikely or where failure of more than one set of power units would bring down the entire installation. In another embodiment for the monitoring of four or more sets of power units, the 2-out-of-3 selection circuit is preceded by a selection unit, from which the measured values of the entire power unit, each excluding its own, are derived.

From the measured values derived therefrom, the selection unit selects two sets of measured values relating to the operating power unit. The measured values of a failed or disconnected unit are replaced by the measured values of a unit that is still in operation. This type of installation can therefore still be reliably monitored even in the event of a failure of one or more power units. Another arrangement of the invention for monitoring installations with four or more power units is to use high-level selection circuits, such as 3-out-of-4 selection circuits or 4-out-of-5 selection circuits.

The present invention will be explained in more detail below with reference to the drawings.

In FIG. 1, a load 1 is connected to a bus S, and this bus S
Power is supplied from a plurality of power units 2a, 2b, and 2c.

Each power unit 2a, 2b, 2c has a
Devices 4a, 4b, 4c are provided for shredding the unit. These shredding devices can be realized by known means such as electronic, mechanical, pneumatic, or hydraulic. Each cutting device can also be included in a regulating device attached to the associated power unit. Each power unit includes a detector 3a for detecting operating characteristic parameters,
3b and 3c are attached. The measured values of the three sets of detectors are converted into distinguishable signals depending on the case, and then
It is led to a 2-out-of-3 selection circuit with monitoring devices 5a, 5b, 5c.

The output signal of each monitoring device is coupled in such a way that it can act on the power unit to which it belongs, or the disconnection path, so that when the monitoring device issues an appropriate operating command, the power unit to which it belongs is immediately disconnected. There is. Each monitoring device, e.g. 5a, has two
It has a pair of differential circuits 6, 7, threshold circuits 8, 9 modified after these, and a logic circuit 10, the logic circuit 10 logically combining the output signals of the threshold circuits 8, 9, An operation command is issued to the shearing device 4a to shred the attached power unit 2a.

The inputs of the differential circuit 6 include the measured values of the operating characteristic parameters of the associated power unit 2a and the adjacent power unit 2a.
The measured values of the operating characteristic parameters of b are derived. Similarly, the input of the differential circuit 7 receives the measured values of the operating characteristic parameters of the associated power unit 2a and the third power unit 2c.
Measured values of operating characteristic parameters are derived. In this way, in the monitoring circuit 5a, the power unit 2 to which it belongs
It has a function of comparing the measured value of the operating characteristic parameter of power unit a with the measured value of the operating characteristic parameter of the other power units 2b and 2c.

If all three sets of power units are not faulty, there will be no or only a small difference in the measured values of the operating characteristic parameters of the three sets of power units. Therefore, the threshold circuits 8 and 9 do not generate any output signals, and the AND circuit 10 also does not output any output. On the other hand, if a failure occurs in the power unit 2a, the measured values of the operating characteristic parameters will differ from the remaining constant values on both sides. Differential circuits 6 and 7 form output signals that exceed the operating values of function value circuits 8 and 9, respectively. Both function value circuits 8 and 9 commonly output an output signal similar to that outputted by the AND circuit 10, and the AND circuit 1 is a device for disabling the corresponding operation command from the malfunctioning power unit 2a. Emit at 4a. If a failure occurs in the power unit 2b or 2c, the threshold circuit 8
Only the threshold circuit 9 operates.

Therefore, a signal is applied to only one input of the AND circuit 10. Therefore, the AND circuit 10 does not issue an operation command to shut down the monitoring device 2a. Obviously, a faulty power unit 2b or 2c is disconnected by the associated monitoring device 5b or 5c. 2a to 2c show an advantageous embodiment of the invention in the monitoring of auxiliary power installations.

Load 11 is connected to reliable bus RST. During non-fault operation, current is supplied from the grid to each current generator GR.
The conversion is performed through three sets of conversion devices as a power unit including 1, GR2, GR3, batteries B1, B2, B3, and inverters W1, W2, W3. When the grid voltage is absent, the load 11 is supplied with power from the batteries BI to B3 via the inverters WI to W3. Three sets of converter pupils are operated in parallel, each supplying 1/3 of the required load power in the event of a failure.

If a failure occurs in one of the converters, the failed converter is immediately disconnected, and the remaining converters share and supply the necessary load power. Therefore, the converters are designed capacitively such that each converter can supply half of the required maximum load power. As operating characteristic parameters, the output phase currents of the three sets of inverters WI to W3 are detected and monitored.

This is because each failure in the converter is noticeable in its load condition. Therefore, the instrument current transformer WR
,,Ws,,WT, or WR2, Ws2, no WT2, and WR3, Ws3, W3 are provided. current transformer WR
, the terminals of aR, . bR, and the terminals of other current transformers are similarly shown. Relays ○1, D2, and D3 are provided as devices to disconnect the converter. Figure 2b shows the configuration of the monitoring device.

This monitoring device is attached to a conversion device that has a rectifier GR1, a battery B1, and an inverter WI, and an IJ radar D as a device for cutting off this conversion device.
It controls I. The monitoring devices for both other converters are constructed in exactly the same way. The illustrated monitoring device is connected on its input side to the secondary terminals of the voltage transformer. The numbers of the input terminals correspond to the corresponding appearance in FIG. 2a. The generation of the difference takes place in a three-phase manner with differential current transformers DWI to DW6.
Each differential current transformer supplies burden resistors RI to R6 via bridge rectifiers 13 and 18. A maximum voltage drop across resistors R1, R3, R5 is introduced at terminal 32 by a maximum value circuit with diodes nl, n3, n5, respectively. The maximum voltage drop across resistors R2, R4, R6 is introduced at terminal 31 by a further maximum selection circuit with diodes n2, n4, n6. Terminal 31 is connected to negative potential N via resistor R8, and terminal 32 is similarly connected to negative potential N via resistor R7. Resistor R7 loads the maximum selection circuit with diodes nl, n3, n5. The load current flowing through the diode acts in such a way that the diode is placed in the current-carrying region and operates in the linear part of its characteristic curve. Furthermore, this resistor R7 causes the diode n to be activated at each instant in the delay circuit 19 of the subsequent layer, independent of the state of charge of the energy storage device, in particular the capacitor.
l, n3, and n5 ensure accurate selection of the maximum value. A bidirectional low resistance connection is provided to the diode. At each instant, a voltage of a height proportional to the magnitude of the maximum difference current between the in-phase output currents of the two sets of inverters appears at terminals 3--32. It is led to the open value circuit 20 or 26 via the delay circuit 19 or 25. The operation of this special function value circuit will be explained in detail later with reference to FIG. 2c. controls the electronic switches 21 and 27, and the electronic switches 21 and 27 open and close the relays 22 to 28. An AND circuit is configured through the contacts of both relays 22 and 28. The positive potential P is Contact 22b of relay 22 and relay 28
is led to the input terminal 30 of the relay DI via the contact 28b. If only one of the relay contacts 22b or 28b is opened, the relay DI is supplied with current from the potential P via the relay contact that is still closed. Triangle circuits 20 and 2
Relays 22, 2 only if 6 gives a corresponding output signal.
8 is deenergized, relay contacts 22b and 28b are opened,
The current supply to relay DI is cut off. Relay DI is thereby deenergized and disconnects inverter WI from reliable bus RST on the output side. Potential P is connected to indicator light 29 via other contacts 22a and 28a of relays 22 and 28.

The indicator light 29 lights up during non-fault operation. A fault within the monitoring device will act to de-energize one of both relays 22 and 28. In this case, the indicator light 29 goes out, but the relay DI
continues to be energized. If the monitoring device has an internal failure, the relay DI
This is confirmed by turning off the indicator light 29 without being turned off. In the event of a certain fault in the monitoring device, for example a power supply fault, both relays 22 and 28 are deenergized.

In this case, the relay DI is also erased. Such a relationship is
This is desirable since further operation of the installation without functional monitoring equipment is thereby avoided. A simple test of the monitoring device is possible using the indicator light 29. A short circuit across the terminals of one of the adjacent current transformers will cause a difference between the measured values during non-faulty operation. At that time, in a normally operating monitoring device, one of relays 22 or 28 is deenergized and indicator light 29 goes out. The terminals of the current transformers of all three phases are short-circuited one after another, and the indicator light 29
All functions of the current transformer and the monitoring device can be tested without brightness disturbances or interruptions in operation by checking whether the current transformer and the monitoring device disappear.

FIG. 2c shows the internal connection configuration of the delay circuit 19 and the function value circuit 20 in FIG. 2b.

The delay circuit 19 is configured as a third-order active filter,
It includes an operational amplifier 33 and capacitors 34, 35, and 36 connected as shown. Delay circuit 19 delays the voltage step at its input terminal 32 according to its transient response. The threshold circuit 2 includes a positive feedback resistor 39 and an operational amplifier 37 wired as a jump amplifier with an operating threshold adjustable by a potentiometer 38.
The delay circuit 19 is a Zener diode 2 as a threshold circuit.
Shorted by 3. A feedback effect from the output side of delay circuit 19 is blocked by diode 24. When the voltage step at the input terminal 32 exceeds the Zener voltage of the Zener diode 23, the function circuit 20 bypasses the delay circuit 19 and is directly controlled. The threshold circuit 20 then operates without delay. A voltage step below the Zener voltage of the Zener diode 23 is delayed according to the transient response of the delay circuit 19. The time it takes for the threshold circuit 20 to respond is inversely proportional to the voltage step at the input terminal 32 and thus to the magnitude of the difference current in this region. FIG. 3 shows in principle an application of the invention for monitoring two sets of power units 2a and 2b supplying a load 1 via a common bus S. In FIG.

Once again, both power units 2a and 2b are associated with detectors 3a and 3b for detecting operating characteristic parameters, as well as devices 4a and 4b for disconnecting the power units. Furthermore, a model unit 2* with a model adjustment device 4* and a detector 3* is provided. The model unit 2* corresponds in the behavior of at least one of the at least one operating characteristic parameter to that of the other power unit. It therefore behaves in the same way as one of the two power units 2a and 2b, at least with respect to its operating characteristic parameters of interest. The model unit 2* can in principle be constructed like a scaled-down power unit. Moreover, although the model unit 2* can also be supplied to a common bus S, it supplies only a very small part of the required load power.
However, on the other hand, it is also possible to use a power unit simulator, which can consist of electronic, mechanical, pneumatic or hydraulic means.

For processing within the monitoring devices 5a, 5b, 5c, the signals of the detectors 3a, 3b and the output signal of the detector 3* are brought to the same level.

This can be done by using a detector 3* which supplies the model unit 2* with an output signal varied by a certain proportionality constant. however,
It is also possible to equalize the output signal of the detector 3* or the output signals of the detectors 3a, 3b to the same level via a signal converter. In that case, the aligned signals are transmitted to the monitoring devices 5a and 5b.
, 5c directly in the manner already described. If a failure occurs in either power unit 2a or 2b, that power unit will be shut down. In the case of a failure of model unit 2*, this unit is likewise cut off. Furthermore, it is advantageous if it is indicated that the supervisory control device is non-functional. FIG. 4 shows this principle in two models each equipped with adjusting devices 42a and 42b.
This shows an example of the configuration when applied to a power supply device having a pair of converters 41a and 41b.

Both converters 41a, 41b feed a common bus to which a load 40 is connected. Furthermore, a transducer model 41* with a regulating device 42* is provided. Converter model 41*
is designed to have a small capacity, and its load distribution is configured to correspond to the load distribution of both monitoring converters 41a and 41b. The emitted power, which is smaller by a proportionality constant than the capacitance of the transducers 41a, 41b, is likewise supplied to the bus bar. The load current is introduced from a current detector 45 and the bus voltage from a voltage detector 46 as input quantities to the regulating devices 42a, 42b and 42*.

Furthermore, the corresponding setpoint and actual values of the associated transducer are applied in a known manner to the regulating device. The output current of the converter is evaluated as an operating characteristic parameter. Therefore converter 4
Current transformers 64 and 65 are provided on the output side of 1a and 41b. A current transformer 66 is attached to the converter model 41*, and its current transformation ratio differs from the current transformation ratios of both current transformers 64 and 65 by a model constant. By doing this, converter 4
1a, 41b and the current measurement value of the converter model 41* are monitored by the monitoring device 5a of the 2-out-of-3 selection circuit.
5b and 5c, it becomes possible to directly compare them with each other. Monitoring devices 5a and 5b control relays 43a and 43b which, in the event of a fault in either converter, disconnect the faulty converter from the busbar. The converter model 41* is monitored by a monitoring device 5c. The switching off of the converter model 41* takes place via a relay 43*, which has an auxiliary contact for the indicator light 44. Disconnection of the converter model 41* does not adversely affect the operation of the installation, but results in the selective monitoring no longer functioning. In this case, the indicator light 44 goes out. Converter 41 as converter model 41*
Transducers constructed similarly to a to 41b can be used, but suitably smaller components are then used.

However, it is also possible to provide an electronic simulation of the transducer. FIG. 5 shows an inverter circuit and its electronic simulation device.

The inverter shown in FIG. 5a has its input terminal 47
and 48 are connected to the battery.

This inverter includes controllable electric valves nl1 to n16 and n21 to n26, which are controlled by a control device which is not shown in detail. The three-phase RST appears at the output terminals of the transformer as phase voltages UT, Us, UR.

The electronic simulator of the inverter circuit shown in FIG. 5b is also provided on the input side with input terminals 47 and 48 for the battery voltage or a voltage proportional to the battery voltage.

Furthermore, an input terminal for the ignition pulse of the controllable electric valve is provided. The corresponding input terminals are nll to n16 and n2.
No 1, indicated by n26. For example, input terminal nl
l is connected to the ignition pulse conductor for electric valve nll.
The ignition pulses for the main valve and the extinguishing valve of one polarity of one phase of the inverter output voltage are provided by a flip-flop 49, respectively.
54 to any of the set or reset inputs. For example, a firing pulse for the valve nll is applied to the set input of the flip-flop 49, and a firing pulse for the extinguishing valve n21 is applied to the reset input of the flip-flop 49. The output signal of flip-flop 49 controls electronic switch 55. The flip-flop 52 is controlled at its input by the ignition pulses for the main valve n14 and the extinguishing valve n24 of the opposite polarity of the relevant phase of the inverter output voltage. The output signal of flip-flop 52 controls electronic switch 56. Both switches 55 and 56 alternately connect the positive and negative polarities of the battery voltage to the input of the operational amplifier 57. A voltage corresponding to the inverted phase voltage of the inverter appears at the output of the operational amplifier 57. An inverting amplifier 58 follows the operational amplifier 57, the output voltage of which forms the phase voltage of the inverter. The phase voltage and the inverted phase voltage are each converted into a phase-to-phase voltage in a further operational amplifier 59 connected as a summing amplifier.

The output signal of operational amplifier 59 is further inverted by another inverting amplifier 60. By recombining the phase-to-phase voltages and the inverted phase-to-phase voltages in the operational amplifiers 61, 62, and 63 connected as summing amplifiers again, the simulated phase voltages UR*, U
s*, UT*, but this simulated phase voltage is
a shows the same variation of the actual phase voltages UR, Us, UT at the output of the transformer of the inverter circuit shown in figure a. 4
A configuration similar to FIG. 1 is used for monitoring installations with a set or more power units operated in parallel.

FIG. 9 shows that each power unit 2a to 2d has a detector 3a to 3d for detecting operating characteristic parameters and a monitoring device 5a to 5.
d, and a device 4a for cutting off the power unit.
4d shows the monitoring circuit attached. Each monitoring device 5a
The measured values of the operating characteristic parameters of the own power unit and the corresponding measured values of the other two sets of power units are introduced to the input side of ~5d. If only one power unit fails, that failed unit is immediately disconnected. Accordingly, this monitoring circuit no longer functions. Therefore, the insertion of a monitoring circuit of this type is suitable for installations where the failure of only one set of power units is taken into account, or where the failure of more than one set of power units requires the entire installation to be shut down. Are suitable. Figure 6 shows that the 2-out-of-3 selection circuit can also be applied to equipment with four or more power units operating in parallel, where the monitoring function must be maintained even in the event of a failure in the power unit. The principle configuration of a possible selection unit is shown. According to the configuration of the invention, a selection unit of this type is provided in advance of each monitoring device of the 2-out-op-3 selection circuit.
A selection unit 74 is installed in the monitoring device 5a, and its input side is connected to detectors 3b and 3 of a power unit (not shown).
c, 3d.

This selection unit 74 furthermore has input terminals 72 and 73, to which the operating fault signal is applied. This operation failure signal is generated when the related power unit is notified that it has failed and is then shut off. For this purpose, for example, an operating command of a monitoring device is applied to the set input of a memory for the failure of a faulty power unit, the output of which produces an operating fault signal. The memory is put into operation again during a new start-up of the power unit after the fault has been removed. The operational fault signal at input terminal 72 indicates that the power unit to which detector 3b is attached is faulty. Further, the operation failure signal at the input terminal 73 indicates that the power unit to which the detector 3c is attached is malfunctioning. The selection unit 74 has two relays 70 and 71, the contacts of which are connected to the detector 3 as shown.
b, 3c, 3d and output terminals 75 and 76.

When all four sets of power units are operating without failure, all IJ relay contacts are in the state shown.

The measured value of the detector 3b is guided to the output terminal 75, and the measured value of the detector 3b is
The measured value of c is led to output terminal 76. The measurement value of its own detector 3a and the measurement values of detectors 3b and 3c are added to the input of the monitoring device 5a. In the event of a failure of the power unit with detector 3d, this state remains unchanged.

Since the monitoring device 5a receives the measured values of the three non-faulty power units having the detectors 3a, 3b, 3c, the monitoring device 5a continues to have its function. In case of failure of the power unit with detector 3b, terminal 72
An operational failure signal is generated and relay 70 is energized.

Relay contact 70a is opened and relay contact 70b is closed. Therefore, the measured value of the detector 3d is connected to the output terminal 75. Now again the monitoring device 5a includes the detector 3a,
The measured values of the three non-faulty power units having 3c and 3d are added. In the event of a failure of the power unit with detector 3c, an operating failure signal is generated at terminal 73 and relay 71 is energized.

Relay contact 71a is opened and relay contact 71b is closed. The measured value of the detector 3d is led to an output terminal 76.
The illustrated selection unit can be extended to any number of detectors in a similar manner.

In FIG. 6, only the principle of the selection unit is explained. A selection unit of this type can also be constructed in other ways by electronic, mechanical, pneumatic or hydraulic means. The selection unit excludes the measurement values of its own power unit from the measurement values introduced therein and extracts the two sets of measurement values of the non-faulty power unit 2 out of 3.
It is important to ensure that the selection circuit communicates the selection to the monitoring device. Another embodiment for the monitoring of installations with four or more power units operated in parallel consists in inserting a high-level selection circuit, for example a 3-out-of-4 selection circuit.

FIG. 7 shows the basic configuration of a monitoring device 77b for a 3-out-of-4 selection circuit. The measurement values of the detector 30 of the own power unit and the measurement values of the detectors 3a, 3c, and 3d of the other power units are introduced to the input of the monitoring device 77b. The monitoring device 77b includes differential circuits 78, 79, 80,
In addition to this, threshold circuits 81, 82, 83, AND circuits 84, 85, 86, and OR circuit 87 are provided.
In the interpolation circuits 78, 79, and 80, the measured values of the detector 3b of its own power unit are compared with the measured values of the detectors 3a, 3c, and 3d of the other power units. Then, when the difference between the two measured values exceeds a predetermined threshold value, the threshold value circuit 81 in the subsequent layer operates. The inputs of the AND circuits 84, 85, 86 are the function value circuits 81, 82.
, 83 and are cyclically rearranged and connected. The output signals of the AND circuits 84, 85, and 86 are each collected into an OR circuit 87, and the output signal of the OR circuit 87 becomes an operation command for cutting off the associated power unit. In the event of a failure of the associated power unit with detector 3b,
All three sets of differential circuits 78, 79, and 8 output signals that exceed the response values of the function value circuits 81, 82, and 83 sent later. Therefore, all three sets of AND circuits 84, 85, 86 output output signals. That is, the output of the OR circuit 87 is given a suitable operating command for cutting off the power unit. This operating command appears even if the corresponding output signal of the stop value circuit 83 is not generated, for example due to a failure of the differential circuit 80 or the stop value circuit 83. both channels 78,
Since 81, 79, and 82 can still operate, the AND circuit 84 outputs an output, and the output signal is provided via the O circuit 87 as an operation command for cutting off the power unit. Therefore, the function of the monitoring device 77b is guaranteed even in the event of a specified failure of the monitoring device 77b. FIG. 7a shows a device for monitoring four sets of power units, which is constructed using the monitoring device for the 3-out-op-4 selection circuit shown in FIG.

In FIG. 7a, for example, assume that only the power unit 2a has malfunctioned. Similar to the monitoring device 77b shown in FIG. 7, the monitoring device 77a uses the measured values of the detector 3a of its own power unit 2a and the detectors 3b, 3c,
Therefore, the differential circuits 78, 79, and 80 output difference outputs that exceed the corresponding threshold values of the threshold circuits 81 to 83, and the function circuits 81 to 83 are activated. be done. Here, for example, the dark value circuits 81 to 83 transmit a logic signal "1" when a difference output exceeding the response threshold value is transmitted from the differential circuits 78 to 80; If a difference output exceeding the response threshold value is not transmitted from 80, a logic signal "0" is transmitted. Therefore, in the monitoring device 77a, all "1" signals are transmitted from the dark value circuits 81 to 83, and therefore the AND circuit 8
All "1" signals are also transmitted from 4 to 86. As a result, the device 4a is activated via the OR circuit 87, and the power unit 2a is controlled to shut off. On the other hand, at this time,
In the monitoring circuit 77b, the differential circuit 78 sends out a differential output that exceeds the response threshold of the threshold circuit 81, but the differential circuits 79 and 80 have power units 2b, 2c, and 2c operating normally, respectively. 2d each detector 3b, 3c, 3d
Since the measured value is supplied, the differential outputs exceeding the response values of the threshold circuits 82 and 83 are not transmitted from the differential circuits 79 and 80.

Therefore, a “1” signal is transmitted from the function value circuit 81,
A "0" signal is transmitted from each of the threshold circuits 82 and 83. Therefore, the AND circuits 84-86 all output "0" signals, and therefore the device 4b is not activated. Such operation also applies to the monitoring circuits 77c and 77d. Therefore, in the end, the power unit 2 that caused the failure
The other three power units 2b, 2c, and 2d, which are operating normally, remain as they are by only controlling power unit a to be turned off. FIG. 8 shows the basic structure of another embodiment of a monitoring device for a 3-out-of-4 selection circuit.

This monitoring device 88b again monitors the measured values of the detector 3b of its own power unit, the detectors 3a of other power units,
It is controlled by the measured values of 3c and 3d. The measured values of the four sets of detectors are guided to differential circuits 90, 91, and 92 as shown in the figure, and function value circuits 93, 94, and 95 are provided behind the differential circuits 90, 91, and 92, respectively. .

The outputs of the function value circuits 93, 94, and 95 are each connected to the input side of an AND circuit 89. The output signal of the AND circuit 89 becomes an operation command for cutting off the power unit to which the detector 3b is attached. Monitoring device 77 in FIG.
The monitoring devices 88b and 88b in FIG. 8 differ in their reliability in the event of their own failure.

That is, although the monitoring device 77b continues to function even if a certain channel including the differential circuit and the threshold circuit is inactive,
The situation is different for the monitoring device 88b. Therefore, the selection of both of these monitoring devices is determined depending on whether or not there is a possibility that the reed circuit or the threshold circuit will not operate. The monitoring of a plurality of power units operated in parallel in the partial load range can be improved in that the response threshold of the threshold circuit in the monitoring device is followed by a quantity characterizing the total power amount.

By taking such measures, a high and constant sensitivity of the monitoring can be obtained even if the load in the partial load region does not take up its full rated capacity. In the partial load range, correspondingly small deviations in the operating characteristic parameters detected for the individual power units lead to a fault signal or to the failure of the failed power unit. If this configuration of the invention is applied for the monitoring of a plurality of power plants operated in parallel, it is advantageous to use the composite load current as the quantity characterizing the composite power. This means that the reactive value of the dark value circuit of the individual monitoring device is tracked as a function of the composite load current.
Three sets of power units 2a, 2b shown in FIG. 10a
, 2c, in its configuration the device for monitoring the first
Corresponds to the diagram.

An instrument current transformer 96 is provided to sense the composite load current, the output terminals of which are shown at 96a and 96b.
Figure 10b shows the internal configuration of a threshold circuit, for example, a threshold circuit, and this internal configuration is the second in principle in its configuration.
This corresponds to the circuit example shown in Figure c. The dark value circuit 8 has a delay circuit 19 and a limit value annunciator 20'. The limit value annunciator 20' also includes a feedback resistor 39 and a potentiometer 97.
It has an operational amplifier 37 wired as a jump amplifier with a response threshold that can be adjusted by . Potentiometer 97 connects terminal 96 of current transformer 96 to detect the composite load current.
a and 96b. In this way, the response threshold value of the limit value annunciator 20' is followed depending on the composite load current. This allows the monitoring and control device to operate more sensitively in the partial load region than in the full load region. Another advantageous embodiment of the invention concerns the monitoring of several power units operated in parallel with different rated capacities.

In this case, in order to detect the operating characteristic parameters, potential current transformers are used, each with a selected transformation ratio corresponding to a different rated capacity, or a negative voltage is introduced via a voltage divider. In addition, the same type of instrument current transformer is used, the voltage division ratio of which is selected in accordance with the different rated capacity of the power unit. This has the advantage of introducing standardized input voltages into the 2-out-of-3 selection circuit. The selection circuit can therefore have a uniform circuit configuration if a plurality of power units with different rated capacities and operated in parallel are inserted. Figure 11a is the second
This figure shows auxiliary power supply equipment having a basic configuration corresponding to the equipment shown in Figure a.

Load 11 is connected to reliable bus RST. In the case of non-faulty operation, the power supply takes place from the AC power system via the three converters U1, U2 and u as power units. The converters U1 and U2 are rectifiers GR1 and G, respectively.
R2, batteries B1 and B2, and inverters W1 and W2. The converter u is designed to have a small capacity and includes a rectifier gr, a battery b, and an inverter w. Three sets of converters U1, U2, and u are operated in parallel, and in terms of capacity, for example, the maximum required capacity is one of the large-capacity converters UI and U2, and the other is a small-capacity converter. It is stipulated that this can be covered by working together with u.

If either of the large-capacity converters UI and U2 fails, the converter that caused the failure is immediately cut off, and the full load power is shared between the other healthy large-capacity converter and the small-capacity converter U. It will be covered by Small capacity converter u
are selected to be capable of supplying sufficient power to prevent serious damage to the load that could occur if the current supply were to be interrupted, even though they alone cannot supply the required load power. Ru. This may occur, for example, in a data processing device where stored information would be lost if the power supply were completely stopped. In such an application, the small-capacity conversion device u is capacitively defined in such a way that it can supply the necessary holding current for the information memory.
The converter u can also be designed with a small rated capacity so that its capacity is negligibly small compared to the capacities of the other two converters.

In this case, the converter u only supplies comparative values of the operating characteristic parameters to the monitoring devices of both converters UI and U2. Since each failure of a converter is manifested in the state of its load, the output phase currents of the three sets of converters are detected and monitored as operating characteristic parameters.

For this reason, current transformers WR,,Ws,
, WT, and a current transformer WR for the converter U2.
2, Ws2, and WT2 are provided, and current transformers Wr, Ws, and Wt are further provided for the converter u. and, for example, the terminals of current transformer WR, are designated aR,, bR, and the terminals of the other current transformers are designated with similar style symbols. As a device for cutting off the conversion device - D1, D2,
D3 is provided. As is clear from the figure, the potential current transformer attached to the small-capacity converter u has a larger number of turns than the potential current transformer attached to the large-capacity converters UI and U2.

The turns ratio is selected such that when the converter is fully loaded, a standard voltage, for example 10 V, is present in all cases at the terminals of the associated current transformer. FIG. 11b shows a configuration example of a monitoring device that is attached to the conversion device UI and controls the relay J-DI as a device for disconnecting the conversion device UI.

The monitoring devices for both other conversion devices are similarly configured.
The input side of the monitoring device shown in FIG. 11b is connected to the terminals of the potential current transformer.

The numbers of the input terminals correspond to the corresponding terminals in FIG. 11a. The circuit design of this monitoring device corresponds to the monitoring device shown in FIG. 2b. As can be seen from FIG. 11b, the individual channels of the monitoring device are constructed identically, and each input is connected to an instrument current transformer attached to a large-capacity conversion device UI or U2. Alternatively, there is no need to consider whether the input is connected to the potential current transformer of the converter u having a small capacity.

There are no differences in circuit technology to the configuration of the monitoring device shown in FIG. 2b.

[Brief explanation of the drawing]

The figures each show an embodiment of the present invention, and Fig. 1 is a connection diagram showing an example of a device for monitoring three sets of power units, Fig. 2a is a connection diagram of an auxiliary power supply facility having three converters, Fig. 2b is a connection diagram showing an example of the selection circuit applied to the equipment shown in Fig. 2a, Fig. 2c is an internal connection diagram of the step-value circuit in Fig. 2b, and Fig. 3 shows two sets of circuits operated in parallel. Principle connection diagram of the device for monitoring the power unit,
Figure 4 is a connection diagram of a device having two sets of power supplies operated in parallel, Figure 5a is a connection diagram of an inverter circuit with an output transformer, and Figure 5b is a connection diagram of a simulated circuit of the inverter circuit in Figure 5a. 6 is a connection diagram showing an example of a selection unit of a device for monitoring four sets of power units, and FIG.
The figure is a connection diagram of an example of a 3-out-of-4 selection circuit, and FIG. 7a is a connection diagram of a device for monitoring four sets of power units configured using the 3-out-of-4 selection circuit shown in FIG. 8 is a connection diagram of another example of a 3-out-of-4 selection circuit; FIG. 9 is a connection diagram of a supervisory control device for four sets of power units; and FIG. Fig. 10b is a connection diagram of a limit value alarm applied to the circuit of Fig. 10a, Fig. 11a is a connection diagram of an auxiliary power supply facility having three sets of inverters, Fig. 11b is a connection diagram showing an example of a device for The figure is a connection diagram showing an example of a selection circuit for the equipment of Figure 11a. 1, 11, 40...Load, 2a, 2b, 2c,
2d... Power unit, W1, W2, W3... Inverter, 41a, 410, U1, U2... Conversion device, 3a
, 3b, 3c, 3d...detector, WR,, Ws
,,WT,,WR2,Ws2,WT2,WR3,Ws3
, WT3, 64, 65...Instrument current transformer, 4a, 4b,
4c, 4d...Shrinking device, D1, D2, D3
, 43a, 43b...Relay, 5a, 5b, 5c, 5d
... Monitoring device, 6, 7 ... Differential circuit, 8, 9 ...
- Function value circuit, 10...AND circuit. Fig. lFig. 3Fi9, 23 Fig. 2b Fi9.2c Fig. Fig. 5a Fi9.5b Fi9.6 Fig. Fig7o Fig. 8 Fig. 9Fig. 10aFig. '0b Fi9.11a Fig. lib

Claims (1)

[Claims] 1 At least three sets of power units are operated in parallel and each output power is directed to a common load, each power unit is equipped with a detector for detecting the measured value of the same type of operating characteristic parameter, and a power unit. A shearing device for cutting the power source and a monitoring device are attached, each of the monitoring devices being configured to monitor the measured values of operating characteristic parameters of the power unit to which each monitoring device belongs and the operating characteristics of at least two sets of other power units. Each measured value of the parameter is introduced,
Each monitoring device has a function of comparing the former measured value and at least two latter measured values, and each monitoring device has a predetermined distance between the former measured value and the latter at least two measured values. When a difference exceeding a response threshold occurs, actuating a shearing device belonging to the monitoring device to which the former measurement value is introduced, and controlling the power unit to which the monitoring device belongs, to cut off the power unit; A power unit monitoring/control method characterized by: