RU2785323C1 - Device for preventive protection of ship electric power system - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to the field of electrical engineering, in particular to devices for preventive protection of the ship's electrical power system. The effect is achieved by the fact that in the device for protecting the ship's electric power system, containing, according to the number of generating units (GU): active load sensors, GU technical condition control units, GU operation sensors, as well as an GU start mode identification unit and a GU start unit, while outputs active load sensors are connected to the first corresponding inputs of the GU start mode identification block, the outputs of the HA technical condition control blocks are connected to the corresponding second inputs of the GU start mode identification block, the outputs of the operation sensors are connected to the third corresponding inputs of the GU start mode identification block, while the unit is additionally turned on disabling consumer groups and a delay unit, wherein the output of the identification block for the start mode of the GU is connected to the input of the block for disconnecting consumer groups and the input of the delay unit, the output of which is connected to the input of the start block of the GU.

EFFECT: increasing the reliability of control when generating commands to start an emergency generating set.

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Description

The invention relates to the field of electrical engineering and can be used for preventive protection of ship electrical power systems (SEES).

A device for protecting the SEES network is known (A.P. Baranov. Ship automated electric power systems: Textbook for universities. 2nd ed., Rev. and additional / St. Petersburg: Shipbuilding, 2005. -, 440 p.), which, when power failure in the network starts the emergency diesel generator set (AGA). The device allows you to restore the power supply to critical power receivers operating in emergency mode, until the start of the standby generator set (GA).

The disadvantage of the device is that it takes time to start the AGA, during which the ship's steering, fire and bilge pumps, the main propulsion system of the ship and other consumers of electricity, the safety of the ship and crew depend on, do not work.

The closest analogue of the claimed device, taken as its prototype, is a device that implements a method for protecting the ship's electrical power system (patent RU 2 681 940 C1 H02J 9/00 (2018.08); H02J 9/06 (2018.08) published: 03/14/2019), according to which, upon transition of one or more of the operating generator sets (GA) to a faulty state, a command is generated to start the emergency generator set (AGU) until the faulty (faulty) GA is turned off, provided that the SEES is in the operating mode, in which the shutdown of the operating faulty (working) faulty) GA will lead to the disappearance of voltage in the network. The device implementing the method contains according to the number of HAs: active load sensors, HA technical condition control units, HA operation sensors, as well as an AHA start mode identification block and an AHA start-up unit, while the active load sensor outputs are connected to the first corresponding inputs of the AHA start mode identification block , the outputs of the GA technical condition control units are connected to the corresponding second inputs of the AGA launch mode identification block, the outputs of the operation sensors are connected to the third corresponding inputs of the AGA start mode identification block, the output of which is connected to the input of the AGA start-up block.

This device allows in advance, before the disappearance of voltage on the busbars of the main switchboard (MSB), to start the AGA, which in most cases ensures the transition from the main to the emergency power supply for critical consumers without interruption in the power supply. In this regard, it is a preventive protection device for SEES. The disadvantage of this device is the low reliability of the control algorithm, which means that when generating a command to start the AGA, the action of other devices that ensure the protection of the SEES is not taken into account. In this regard, a situation is typical in which the shutdown of a functioning faulty (faulty) GA will lead to the fact that the load of any of the remaining serviceable GAs will be higher than the permissible value after the faulty GAs are turned off. If at the same time, simultaneously with the command to start the AGA, a command is given to turn off consumer groups, then it may turn out that at the moment when the AGA is started, the network load will be such that after disconnecting the faulty HAs, the load of all remaining serviceable HAs will not exceed the allowable value. In this case, the launch of the AGA will be erroneous, which characterizes the methodological error of the algorithm implemented by the device taken as a prototype and significantly reduces its reliability. Obviously, the operating principle of the device, taken as a prototype, is methodically based on low control reliability, which means that in certain operating modes of the SEES, this device will launch the AGA in a situation where this is not required, i.e. will false start the AGA.

The purpose of the present invention is to increase the reliability of control when generating a command to start the AGA by eliminating false starts of the AGA.

To solve this problem, the following set of essential features is used: in a device for protecting the ship's electric power system, containing, like the prototype, according to the number of GA: active load sensors, GA technical condition monitoring units, GA operation sensors, as well as an AGA launch mode identification unit and an AGA start-up unit, wherein the outputs of the active load sensors are connected to the first corresponding inputs of the AGA start-up mode identification block, the outputs of the HA technical condition control units are connected to the corresponding second inputs of the AGA start-up mode identification block, the outputs of the operation sensors are connected to the third corresponding inputs of the mode identification block startup of the AGA, unlike the prototype, an additional block for switching off consumer groups and a delay block are additionally included, while the output of the block for identifying the start mode of the AGA is connected to the input of the block for disconnecting consumer groups and the input of the delay block, the output of which is connected to the input of the start block say AHA.

The essence of the invention lies in the fact that, unlike the prototype, the launch of the AGA is not carried out immediately when at least one of the operating GAs goes into a faulty state, despite the fact that the load of the SEES is such that disabling the operating faulty (operating faulty) GA will lead to the fact that the load of any of the remaining serviceable HAs will be higher than the permissible value, but only in the case in which the indicated situation persists after the network is unloaded (shutdown of selected consumer groups). This difference is achieved by the fact that the device for protecting the ship's electric power system, taken as a prototype, additionally contains a block for disconnecting consumer groups and a delay block, while the output of the AGA start mode identification block is connected to the input of the block for disconnecting consumer groups and the input of the delay block, the output of which is connected with the input of the AGA launch block. This difference is significant, which makes it possible to exclude false starts of the AGA, since the signal to start the emergency generator is generated after the network is unloaded and takes into account the decrease in its load. At the same time, the command to start the AGA is given until the moment the voltage in the network disappears, which allows us to speak about the preventive protection of the SEES from a blackout.

Comparison of the proposed method and the prototype showed that the task - increasing the reliability of control when generating a command to launch the AGA by eliminating false starts of the AGA - is solved as a result of a new set of features, which proves the compliance of the proposed invention with the criterion of patentability "novelty".

In turn, the conducted information search in the field of power supply did not reveal solutions containing individual distinctive features of the claimed invention, which allows us to conclude that the method meets the criterion of "inventive step".

The essence of the invention is illustrated by the drawing (Figure 1), which shows a functional diagram of a device for preventive protection of the ship's electrical power system.

The proposed device contains according to the number of GA: 1.1, 1.2 ... 1.n - active load sensors, 2.1, 2.2 ... 2.n - control units for the technical condition of the GA, 3.1, 3.2 ... 3.n - GA operation sensors, and 4 - block identification of the AGA start mode, 5 - a block for switching off consumer groups, 6 - a delay block and 7 - a start block of the AGA, while the outputs of active load sensors 1.1, 1.2 ... 1.n are connected to the first corresponding inputs of the AGA start mode identification block 4, the outputs of the blocks control of the technical condition of the HA 2.1, 2.2 ... 2.n are connected to the corresponding second inputs of the identification block of the start mode of the AHA 4, the outputs of the operation sensors 3.1, 3.2 ... 3.n are connected to the third corresponding inputs of the identification block of the start mode of the AHA 4, the output of which is connected to the input of the block for switching off consumer groups 5 and the input of the delay block 6, the output of which is connected to the input of the start block of the AGA 7.

The active load sensor is a well-known functional block similar to the block used in the prototype and generates at its output a signal in the form of a voltage proportional to the active load of the corresponding GA;

the technical condition control unit is a well-known functional unit that generates a logical "1" signal at its output when at least one of the parameters characterizing the operable state of the GA is out of tolerance, the unit is similar to that used in the device that implements the method adopted as a prototype;

GA operation sensor - a well-known functional unit that generates a logical "1" signal at its output when this GA is operating, for example, the contact block of the circuit breaker of the corresponding generator can be used as this unit, similar to the unit used in the prototype;

AGA startup mode identification block - a well-known functional block that provides identification of the SEES operation mode with any number of operating HA (n), in which the shutdown of the inoperative (m inoperative) HA will lead to the disappearance of voltage in the network. The block is similar to the block used in the prototype, determines the load of each of the mn remaining serviceable HAs, compares it with the maximum allowable value for each HA, and if the load of at least one of the remaining operable HAs turns out to be greater than the maximum allowable value Roverload . , then generates a command to start the AGA in the form of a logical "1" signal at its output. Otherwise, if the load of each of the GAs remaining serviceable is less than Roverload , then the signal to start the AGA is not given, at the output of the block - a logical "0"signal;

AGA startup block - a well-known functional block that ensures the launch of the AGA when a logical "1" signal is applied to its input, similar to the block used in the prototype;

consumer group shutdown block - a well-known functional block that disables consumer groups that can be selected in advance (for example, secondary consumers: sauna, residential ventilation, laundry, galley) when a logical “1” signal is received at its input. As a block, an electromagnetic relay can be selected, the opening contact of which is included in the circuit of the minimum release of the automatic switch, through which the shield of secondary consumers of the vessel receives power;

delay block is a well-known functional block that generates a logical “1” signal at its output after a time tset after this signal appears at its input. If during the time tset the signal at the input of the delay block changes from logical "1" to logical "0", then the signal of logical "0" will remain at its output. The delay block can be made in the form of a standard circuit containing RC elements. At the same time, taking into account that the response time of the block disconnecting groups of consumers 5 ( tk ) is usually 20-30 ms, then tset should be chosen somewhat larger, for example, equal to 40 ms.

The SEES preventive protection device works as follows.

When several, for example, n GAs, the GA 3.1, 3.2 ... 3.n operation sensors generate logical “1” signals at their outputs, which are fed to the corresponding third inputs of the AGA 4 start mode identification block. Signals proportional to the load of each GA from the outputs active load sensors 1.1, 1.2 ... 1.n are fed to the corresponding from the first inputs of the AGA start mode identification block 4. m blocks for monitoring the technical condition, a logical “1” signal will be generated and fed to the m corresponding from the second inputs of the AGA 4 launch mode identification block. GA and in the event that the load of at least one of their GAs that remain operational turns out to be greater than the maximum allowable value Rpere gr , then a logical “1” signal will be generated at its output, which will go to the input of the block for disconnecting consumer groups 5 and the input of delay block 6. After a time equal to totk , block 5 will turn off the consumer groups, reducing the load of the SEES. If at the same time it turns out that the load of the SEES has become such that the shutdown of m operating faulty HAs will lead to the fact that, after disconnecting the faulty HAs, the load of any of the remaining serviceable n - m HAs will be less than the value Roverload , then the output of the AHA 4 launch mode identification block will appear the logical "0" signal, which will go to the input of the delay block 6, blocks the appearance of the logical "1" signal at its output, and, therefore, the command to falsely start the AGA will not be given. If, after switching off the consumers by unit 5, the load of the SEES remains such that the shutdown of m operating faulty HAs will lead to the fact that after the disconnection of the faulty HAs, the load of any of the remaining serviceable n - m HAs will be greater than the value Roverload , then at the output of the identification block of the start mode of the AHA 4 the logical “1” signal will remain and after a time tset, a logical “1” signal will appear at the output of the delay block 6, will go to the input of the AGA 7 start-up block, which will start the emergency generating set.

At the same time, we note that it is theoretically possible to select such groups of consumers for any mode of operation of the SEPS, when they are turned off, the load of the SEPS will become such that after disconnecting the faulty HAs, the load of any of the remaining serviceable n - m HAs will be less than the value of Poverload. However, in practice, the design features of the SEES do not allow this, and, as a rule, the load of disconnected consumer groups does not exceed 20% of the rated power of one HA.

Implementation example.

Let's assume that two GAs operate as part of the SEPS - DG1 and DG2 with a rated power of 100 kW each, that is, P1 = P2 = 100 kW. Let the overload capacity of the units be such that each of them can withstand a load of 130 kW ( Poverload = 130 kW), if the load of any of the DGs is greater than Roverload , then this genset will not be able to work and will stop or be turned off by protection against overload. Let us assume that the disconnected consumers create a load equal to 20 kW, the load off time is 0.03 s ( tk = 0.03 s), and the delay time of the delay block 6 (Fig. 1) is 0.04 s ( tset = 0.04 s ).

Assume that the load of DG1 is 80 kW (P1=80 kW) and the load of DG2 is 75 kW ( P2 =75 kW). At the same time, from the active load sensor 1.1 of the device (Fig. 1) to the first of the first inputs of the AGA4 start mode identification block, a signal is received in the form of a voltage corresponding to 80 kW, for example, 8 V, and a signal corresponding to 75 kW, respectively, 7.5 V. Let us assume that a rupture of the lubricating oil pipeline occurred in DG2, while the pressure of the lubricating oil of the diesel engine DG2 will begin to drop sharply and reach a warning value, for example, 0.2 MPa, informing that the GA is faulty, but can still work. At the output of the technical condition control unit 2.1 (Fig. 1), a logical “1” signal will appear and go to the second of the second inputs of the AGA 4 launch mode identification unit. the third inputs of the AGA 4 start mode identification block will receive a logical "1" signal. Since the total network load is 155 kW (Ptot = P1 + P2 = 80 + 75 = 155 kW), then after the GA2 is turned off by the protection, it will fall on the GA1, and will exceed the permissible overload value (155 kW > Roverload = 130 kW). At the same time, a logical “1” signal will appear at the output of the AGA 4 startup mode identification block and will go to the input of the consumer group disconnection block 5 and the delay block 6 input . kW up to 135 kW. Since the obtained value exceeds the allowable value for GA1 overload (135 kW > 130 kW), the logical “1” signal at the output of block 5 will remain and after a time tset = 0.04 s after the start of network unloading, it will appear at the output of delay block 6 and the input block 7. AGA launch block 7 will generate a command to start the emergency generating set, the AGA will start and be ready to receive the load. After the pressure of the lubricating oil of the GA2 diesel engine drops below the emergency value, for example, 0.1 MPa, the GA2 will be disconnected from the network and the entire load of 155 kW will be transferred to the GA1. Since the load of the GA1 will be greater than Roverload , the GA1 will stop or be turned off by the overload protection and there will be a power failure in the SEES network, however, the GA will already be started and will instantly turn on to power the power receivers that ensure the movement of the ship, its controllability and the safety of the crew.

If the SEPS operates in a mode in which the load of the GA is 65 kW, and the load of the GA2 is 60 kW, then in the event of a failure of the GA2, the first unit will have 135 kW of load, which will also exceed the allowable overload value. At the same time, at the output of the identification block for the start mode of the AGA 4, as in the previous case, a logical “1” signal will be generated and will go to the input of the block for disconnecting consumer groups 5 and the input of delay block 6. Block 5 will turn off consumer groups, reducing the network load to 115 kW. Since the obtained value turns out to be less than the allowable value for GA1 overload (115kW <130kW), then 0.03 s after the occurrence of a malfunction in GA2 at the output of the AGA 4 start mode identification block, the logical “1” signal will change to a logical “0” signal. The logical “0” signal from the output of block 4 will go to the input of delay block 6, the logical “1” signal will not appear at its output, the command to start the AGA will not be given. In this situation, the device, taken as a prototype, will give a command to falsely start the AGA.

The proposed invention was created as part of the research work carried out at the Department of Electric Drive and Electrical Equipment of Coastal Installations of the State University of the Sea and River Fleet named after Admiral S.O. Makarov". Calculations were made that showed the possibility of using the proposed device in ship power plants and electric power systems, which, taking into account the above, allows us to conclude that it is possible to use it industrially.

Claims (1)

A device for the preventive protection of the ship's electric power system, containing, according to the number of generating units (GA), active load sensors, GA technical condition monitoring units, GA operation sensors, as well as an emergency generator set start mode identification unit (AGU), a GA launch unit; at the same time, the outputs of the active load sensors are connected to the first corresponding inputs of the AGA start mode identification block; the outputs of the control units of the technical condition of the HA are connected to the corresponding second inputs of the identification block of the start mode of the AHA, the outputs of the operation sensors are connected to the third corresponding inputs of the identification block of the start mode of the AHA, characterized in that it additionally contains a block for switching off consumer groups and a delay block; in this case, the output of the AGA start mode identification block is connected to the input of the consumer group disconnection block and the input of the delay block, the output of which is connected to the input of the AGA start block.

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