Energy management method for an energy supply device in an island grid, and energy supply device

Abstract

The invention relates to an energy management method for an energy supply device (1) in an electrical island grid (2) comprising a plurality of parallel-connected energy supply modules (3), wherein at least one first parameter of a power provided by each energy supply module (3) is monitored with regard to deviations from a respective target value, wherein the first parameter or a second parameter of the provided power is monitored with regard to fluctuations, and the respective energy supply module (3) is shut down on the basis of the deviations and / or fluctuations. The invention also relates to an energy supply device (1) in an electrical island grid (2) comprising a plurality of parallel-connected energy supply modules (3).

Description

[0001]202220837 1 Description Energy management method for an energy supply facility in an island grid and energy supply facility The invention relates to an energy management method for an energy supply facility in an island grid and a corresponding energy supply facility. Dynamic positioning (DP) is a computer-controlled system for the automatic positioning of a ship so that it can maintain a position without anchoring or mooring. The DP positioning of special ships requires an increased protection concept for producing diesel generator sets in order to provide a maximum of available energy for local stock maintenance. For this reason, the diesel generators must be protected by extended protective functions in addition to the usual protective functions covered by the protective device. The protection can also be used as additional protection in all other ship types.New notations such as OP and ER will also require this protection. In these cases, a software solution monitors the parallel operation of the diesel generators and detects malfunctions in parallel operation, so that the individual networks on board can remain interconnected as long as no fault is detected and are only disconnected if necessary, or the faulty set is then disconnected. The protection functions required by the class for the power generators are implemented in the IEDs (intelligent electronic devices), such as reverse overpower, overcurrent, underfrequency, overvoltage and undervoltage, etc. These faults require the complete failure of the devices / systems (mechanical or electrical). However, there are various fault scenarios in which the entire energy system can remain in an intermediate state.In this case, the grid can continue to operate, but performance may be lower or there may be undesirable reactions in downstream systems. This problem was previously solved by supplying the drives via redundant busbar solutions and small island operations, i.e. the generators and drives were distributed across multiple grids so that the failure of one grid had a minor effect on the drive power. However, this solution required a lot of additional hardware, and more diesel generators had to be switched on to ensure the supply to the grids. With DP notation, the supply grid was previously divided into at least two, usually four island grids, so that if one island was lost, only one drive was lost. These islands are then occupied by at least three diesel engines and one drive.Alternatively, two main grids can be defined, which are then separated in DP operation. The individual grids can be separated again in certain fault situations. The entire ship design must be considered here, and it must be determined whether the panels can be located in two or four different rooms. The object of the invention is to provide improved generator protection for an island grid, in which malfunctions of individual power supply modules are detected early on in order to disconnect them from the network.The invention solves the problem directed to a method by providing that in such an energy management method for an energy supply device in an island network with several energy supply modules connected in parallel, wherein at least a first parameter of a power provided by each energy supply module is monitored with regard to deviations from a respective target value, the first parameter or a second parameter of the power provided is monitored with regard to fluctuations and 202220837 3 the respective energy supply module is switched off depending on the deviations and / or fluctuations.The invention solves the problem directed to a method by providing that in such an energy management method for a power supply device in an electrical island network with several power supply modules connected in parallel, wherein at least a first parameter of a power provided by each power supply module is monitored for deviations from a respective target value, that the first parameter or a second parameter of the provided power is monitored for fluctuations and, depending on the deviations and / or fluctuations, the respective power supply module is switched off. The inventive inclusion of the fluctuations in the power parameters in addition to the observations of the deviations from target values ​​enables a faster and more reliable response to possible problems of individual power supply modules in the island network.Advantageously, the first parameter and possibly also the second parameter is an active power setpoint and / or a reactive power setpoint, i.e. the protection enhanced according to the invention consists of monitoring a set's deviation from its active power setpoint – and thus also its frequency setpoint – as well as a deviation from its reactive power setpoint – and thus also its voltage setpoint. Furthermore, it is advantageous if fluctuations in frequency, electrical voltage, active and reactive power are monitored. It is expedient that, if the resulting deviation exceeds a configurable limit, a 202220837 4 alarm and / or a configurable protective function of the corresponding power supply module is triggered.In an advantageous embodiment of the invention, a difference between consecutive measured values ​​of the first or second parameter is determined. If the sign of the difference changes and the difference exceeds a configurable value, this is counted. If a configurable number of alternating sign changes is detected within a configurable time, an alarm is triggered and / or a configurable protective function of the corresponding power supply module is triggered. Advantageously, deviations and fluctuations of one power supply module are compared with deviations and fluctuations of other power supply modules of the power supply device in the island grid.While there is some value in examining individual power supply modules independently of neighboring power supply modules, monitoring the island grid for controller errors is only possible if a central component collects and compares all setpoint and actual values ​​from the individual power supply modules. It is also advantageous to identify a faulty power supply module and test the effect of disconnecting it from the island grid. Software-supported algorithms can identify the power supply module causing the problem, report it to an energy management system, and disconnect it if necessary. Detecting a defect in energy generation and monitoring the response increases the availability of the power grid, allowing DP notations to be implemented with less hardware effort.It is expedient if an alternative is sent to an energy management system if the faulty 202220837 5 energy supply module cannot be disconnected from the energy supply system. The alternative constellation of energy supply modules is also checked in advance for plausibility and availability. The faster a parameter is measured, the faster an energy management system can react to potential errors. It is therefore advantageous if the measurements of at least one parameter of the power provided by a power supply module are carried out with a temporal resolution of at least 500 ms. In an advantageous embodiment of the invention, an energy supply module is monitored for an oversupply or undersupply of fuel. For this purpose, a calculated power is compared with a current power. In the event of an oversupply or undersupplyIf the power falls below a first configurable deviation from a calculated setpoint, an alarm is triggered and if a second configurable deviation is exceeded or falls below a second configurable deviation that is greater than the first configurable deviation, a configurable protective function of the faulty power supply module is initiated.The object directed to a device is achieved by a power supply device in an electrical island network with several parallel-connected power supply modules, the power supply device comprising an energy management system for controlling or regulating the power supply modules, and a monitoring device suitable for measuring performance parameters of the power supply modules, wherein the monitoring device is configured such that, based on the measured performance parameters, a faulty power supply module can be identified and disconnected from the island network by comparison with parameterizable limit values. 202220837 6 Advantageously, the monitoring device is configured such that active power and reactive power are measured.Finally, it is advantageous if the monitoring device comprises at least one island monitoring module and several input and output modules, wherein the input and output modules are arranged near the associated sensors and actuators in the respective power supply module, connected to a respective island monitoring module via a bus system and special head modules or interface modules, and designed to collect setpoint and actual values ​​of the individual power supply modules and forward them to the respective island monitoring module so that the setpoint and actual values ​​of the individual power supply modules can be compared there and recommended actions can be transmitted to the energy management system. The interface modules have a corresponding bus interface (Profibus, Profinet, etc.). Instead of many individual wires to the central CPU, the sensors and actuators only need to be connected to the decentralized periphery (i.e.Input and output modules) are to be wired. From there, only a bus line leads to the CPU. The invention increases the availability of a power supply device in an island network with several power supply modules connected in parallel. In other words, the invention enables a combination of the previously separate islands and thus a reduction in the number of diesel engines required. This saves hardware, as fewer islands are needed, space required for the hardware, and fuel is saved during operation, as the number of diesel engines required can be reduced. Finally, the invention enables closed-bus operation, i.e. operation of the power supply device with a closed busbar, which offers greater tolerance to disturbances in the dynamic positioning (DP), for example of a ship.Without the invention, a ship operating with closed secondary switches would not be guaranteed to remain operational during certain types of power outages. However, rapid restoration of the system is crucial to meeting the DP2 and DP3 minimum requirements, which is why open busbars are often used. The invention is explained in more detail using the drawings as an example.They show schematically and not to scale: Figure 1 an electrical network according to the prior art, Figure 2 another electrical network according to the prior art, Figure 3 an electrical network with an energy supply device according to the invention, Figure 4 an energy supply device according to the invention, Figure 5 a flow chart for determining a meter reading using the example of Active Power Hunting for an individual energy generator module, Figure 6 further actions as a function of a meter reading, Figure 7 the determination of a faulty energy supply module, Figure 8 the monitoring of an energy supply module for an oversupply or undersupply of fuel, Figure 9 evaluation of the deviation for each individual energy supply module, e.g. caused by oversupply / undersupply and Figure 10 the logic of a protective function in the event of an oversupply or undersupply of fuel.Figure 1 shows a schematic and exemplary illustration of an electrical island grid 2 with a prior art power supply device. In the example in Figure 1, it comprises four islands 8, each with an island busbar 9, via which three generators 10 and a motor 11 can be electrically connected. First switches 12 are provided for this purpose. The island busbars 9 can be connected to or separated from one another via second switches 16. In DP (dynamic positioning) mode, all second switches 16 are open, i.e. the island grid 2 then operates with a fully open busbar 13. Figure 2 shows a further electrical island grid 2 with a prior art power supply device, in which two main grids 14 are defined, which are separated from one another in DP mode. These main grids 14 can be further separated into islands 8 in certain fault situations.In the present embodiment of Figure 2, these each comprise two generators 10 and one motor 11. Figure 3 shows an electrical island network 2 with an energy supply device 1 according to the invention, with a busbar 13 that has only a single second switch 16, with which the island busbars 9 of the islands 8 can be connected to or disconnected from one another. In the example of the embodiment of Figure 3, the two islands 8 correspond to two main networks 14. The number of motors 11 and generators 10 required is reduced compared to the prior art configurations of Figures 1 and 2. Figure 4 shows an energy supply device 1 according to the invention, such as could be used, for example, in the electrical island network 2 of Figure 3. The energy supply device 1 extends over two main networks 14 or islands 8.Both main networks 14 each comprise two generators 10 and a battery 15, which are connected via first switches 12 to the respective island busbar 9 and busbar 13, respectively. The two main networks 14 can be connected or disconnected via the second switch 16. The right main network 14 further comprises a shore connection 17. The exemplary embodiment in Figure 4 thus comprises seven energy supply modules 3. The two further modules 3' directly at the second switch 16 are interfaces between the islands 8; although they do not serve to generate energy, they should also be included in the monitoring of the energy supply device 1. A power supply module 3 comprises a network module 18, which serves as an interface to a data network (not further specified) of the inventive energy supply device 1.Furthermore, a power supply module 3 comprises a local power management module 19, which is connected to the network module 18 for transmitting data. The local power management module 19 is also connected to an input and output module 7, which enables communication with, for example, sensors arranged in the respective power supply module 3. Such an input and output module 7 can both receive signals and send outputs. It is essential for the invention that the input and output modules 7 of the power supply modules 3 of an island 8 are connected to an island monitoring module 6. An island monitoring module 6 can, as shown in the embodiment of Figure 4, be arranged in a power supply module 3 or another module 3' itself, but this does not have to be the case. It also fulfills its function outside the power supply modules 3 or the other modules 3'.According to the invention, at least a first parameter of a power provided by each power supply module 3 is monitored for deviations from a respective setpoint, wherein the first parameter or a second parameter of the provided power is monitored for fluctuations and, depending on the deviations and / or fluctuations, the respective power supply module 3 is switched off. The first or second parameter is an active power setpoint (active power) or a reactive power setpoint (reactive power). In particular, fluctuations in frequency, electrical voltage, active and reactive power are monitored. 202220837 10 The active power can be monitored via an internal setpoint of the power supply device 1 or a power supply module 3 and via an actual value measured by the transducer at the generator terminals.Reactive power monitoring requires a setpoint from an AVR (Automatic Voltage Regulator) and a corresponding value measured at the generator terminals. If a deviation of the actual value from the setpoint is detected that exceeds a configurable limit, an alarm is triggered, and a configurable protective function of the defective power supply module is initiated. To check whether so-called "frequency hunting" or "active power hunting" is occurring, alternating changes over time are to be summed. "Hunting" refers to a process in which a system searches for or "hunts" an equilibrium position, which in this case manifests itself, for example, as oscillation of a frequency or active power. Figure 5 shows how this occurs using the example of active power hunting for a single power supply module 3, for example, a generator set.The active power of power supply module 3 is measured using the fastest available method, for example, via the transducer at the generator terminals. The resolution here is approximately 100 ms. In the flow chart shown in Figure 5, the slope of the power curve is determined by calculating the difference from the previous value in each cycle: ^P. n = P n – P n-1 with ^P n = slope of the power curve, P n = currently measured power value and P n-1 = immediately preceding power value. 202220837 11 This gradient ^P n can be positive, negative or 0. If the gradient is within permissible limits, a counter is decreased by 1 (C n = C n-1 - 1). However, if the gradient is greater than a limit ( ^P n > ^P max), each time the direction of the difference changes and the difference exceeds a parameterizable amount, the counter is increased by 1 (C n = C n-1 + 1). If a configurable number of alternating exceedances is detected within a configurable time, a "Frequency / Active Power Hunting" alarm is triggered and a configurable protective function of the corresponding power supply module 3 is activated. In the example in Figure 6, two actions are initiated based on the number of alternating exceedances. In the upper path (C > C A ) an alarm is triggered, in the lower path (C > C T) a trigger is given for the determination of a faulty or defective (D) power supply module 3. Figure 7 shows the necessary steps. First, the number of active power supply modules (#M) is determined. If there are more than two power supply modules 3 on the network (#M > 2), the defective power supply module 3 can be identified by the fact that the deviation of this defective power supply module 3 is distributed among the other power supply modules 3, i.e., the deviation is greatest for the defective power supply module 3. If there are more than two power supply modules 3 per island 8, the one with the greatest deviation is identified. An error counter is incremented for this module (C n = C n-1 + 1), for the remaining power supply modules 3, their respective error counters are reduced (C n = C n-1- 1). In order to have this comparison option, an island monitoring module 6 is provided for each island 8 as a central component, which collectively monitors the deviation of all power supply modules 3. 202220837 12 If the number of active power supply modules is 2 or less, the position of the first switch 16 is checked. If the first switch 16 is closed, an attempt is first made to connect another power supply module 3 in order to identify the faulty power supply module as described in the previous section. If connecting another power supply module 3 is not possible, or if this is unsuccessful, the first switch 16 is opened. If it is already open, it may be necessary to start another power supply module 3 and, when a required power is reached, ieat the appropriate speed and voltage, to connect the active part of the power supply device 1, while the faulty power supply module 3 is switched off. In such a case, a blackout would last in the order of seconds and would only serve to clear the situation. If the error counter (C) of a power supply module 3 exceeds a specified error limit (C. T), this power supply module 3 is switched off, as shown in the lower section of Figure 7. The same principle also applies to the monitoring of voltage hunting. For this purpose, the reactive power of each power supply module 3 is to be monitored. This typically requires the fastest possible measurement of the reactive power at the generator terminals. Figure 8 shows the monitoring of a power supply module 3, for example, an engine (diesel generator) 11, for an over- or undersupply of fuel. For this purpose, the position of the filler rod is read via an analog input. The corresponding signal comes from the corresponding engine 11. This is then converted into an expected generator power using a characteristic curve. This calculated generator power (P set ) is then compared with the current power (P act) at the generator terminals, which is also read in via an analog input from a transducer. 202220837 13 ^P = P act - P set If the deviation ( ^P) exceeds a parameterizable maximum value ( ^P max ) a counter for the deviations is increased: C n = C n-1 + 1 For deviations smaller than the maximum value, the counter is reduced accordingly. C n = C n-1 – 1, ( ^ C n-1> 0) If the nominal power of generator 10 deviates by a configurable number of times, an "overfueling" or "underfueling" alarm is triggered. If a further configurable limit is exceeded or undershot, a configurable protective function for the faulty generator is initiated. The logic of this protective function is shown in Figure 10 and is very similar to the process shown in Figure 7. As in Figure 7, in the example in Figure 10, the number of power supply modules 3 (#M) in the island grid is first determined. As soon as more than two power supply modules 3 are connected to the grid, the faulty power supply module 3 can be identified by the fact that the deviation of the faulty power supply module 3 is distributed among the other power supply modules 3, ie the deviation is greatest for the faulty power supply module 3 (max ^P).If there are more than two power supply modules 3 in the island grid, the one with the greatest deviation is identified. An error counter is incremented for this module (C). n = C n-1 + 1), the error counter of the remaining power supply modules 3 is reduced (C n = C n-1 – 1, ^ C n-1 > 0). 202220837 14 If the number of power supply modules is 2 or less, a check is carried out to determine whether there is a deviation in the ratio of frequency (f) to voltage (U). If there is a positive deviation in the ratio of frequency to voltage ( ^ f / U > 0), the trip counter (C n ) of the power supply module 3 with a positive deviation of active power P to reactive power Q ( ^ P / Q > 0) is increased by one counter (C n = C n-1 + 1). In case of a negative deviation in the ratio of frequency to voltage ( ^ f / U > 0), the trip counter (C n) of the power supply module 3 with a negative deviation of active power P to reactive power Q ( ^ P / Q < 0) is reduced by one counter (C n = C n-1 – 1, ^ C n-1 > 0). If the error counter (C n ) of a power supply module 3 a specified error limit (C T ), this power supply module 3 is switched off, as shown in Figure 10 (and previously Figure 7) in the lower part.

Claims

202220837 15 patent claims 1. Energy management method for an energy supply device (1) in an electrical island network (2) with a plurality of parallel-connected energy supply modules (3), wherein at least a first parameter of a power provided by each energy supply module (3) is monitored for deviations from a respective setpoint, characterized in that the first parameter or a second parameter of the provided power is monitored for fluctuations and, depending on the deviations and / or fluctuations, the respective energy supply module (3) is switched off.

2. Energy management method according to claim 1, wherein the first or second parameter is an active power setpoint or a reactive power setpoint.

3. Energy management method according to one of claims 1 or 2, wherein fluctuations in frequency, electrical voltage, active and reactive power are monitored. 4.Energy management method according to one of the preceding claims, wherein, if the resulting deviation exceeds a parameterizable limit value, an alarm and / or a parameterizable protective function of the corresponding energy supply module (3) is triggered.

5. Energy management method according to one of the preceding claims, wherein a difference between successive measured values ​​of the first or second parameter is determined, wherein if the sign of the difference changes and the difference exceeds a parameterizable value, this is counted, wherein if a parameterizable number of alternating sign changes are detected within a parameterizable time, an alarm is triggered and / or a parameterizable protective function is triggered. 202220837 16 tion of the corresponding power supply module (3) is triggered.

6. Energy management method according to one of the preceding claims, wherein deviations and fluctuations of a power supply module (3) are compared with deviations and fluctuations of other power supply modules (3) in the island grid (2).

7. Energy management method according to one of the preceding claims, wherein a faulty power supply module (3) is identified and the effect of disconnecting this faulty power supply module (2) from the island grid (2) is checked.

8. Energy management method according to claim 7, wherein, if the faulty power supply module (3) cannot be disconnected, an alternative is determined. 9.Energy management method according to one of the preceding claims, wherein the measurements of at least one parameter of the provided power of a power supply module (3) are carried out with a temporal resolution of at least 500 ms, in particular 200 ms.

10. Energy management method according to one of the preceding claims, wherein a power supply module (3) is monitored for an oversupply or undersupply of fuel, wherein a calculated power is compared with a current power, and if a first parameterizable deviation of the power from a calculated target value is exceeded or undershot, an alarm is triggered, and if a second parameterizable deviation, which is greater than the first parameterizable deviation, is exceeded or undershot, a parameterizable protective function of the faulty power supply module (3) is initiated. 202220837 17 11. A power supply device (1) in an electrical island network (2) with a plurality of parallel-connected power supply modules (3), the power supply device (1) comprising an energy management system (4) for controlling or regulating the power supply modules (3), and a monitoring device (5) suitable for measuring performance parameters of the power supply modules (3), characterized in that the monitoring device (5) is configured such that, based on the measured performance parameters by comparison with parameterizable limit values, a faulty power supply module (3) can be identified and disconnected from the island network (2).

12. The power supply device (1) according to claim 11, wherein the monitoring device (5) is configured such that active power and reactive power are measured. 13.Energy supply device (1) according to one of claims 11 or 12, wherein the monitoring device (5) comprises at least one island monitoring module (6) and a plurality of input and output modules (7), wherein the input and output modules (7) are arranged in the respective energy supply module (3) and are designed to collect target and actual values ​​of the individual energy supply modules (3) and to forward them to the respective island monitoring module (6) so that the target and actual values ​​of the individual energy supply modules (3) can be compared there with one another and recommendations for action can be transmitted to the energy management system (4).

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