A method for controlling power management in a microgrid, and a microgrid controller performing such method

Abstract

The disclosure relates to a method for power management in a microgrid located at a mining or a construction project site. The microgrid is detachably connected to an external power grid and have a plurality of interconnected microgrid components including one or more of consumers, power storages and power generators. At least one microgrid component is a combined consumer and power supplier. The method comprises receiving, from said microgrid components, load data representing a current, anticipated and / or planned load on the microgrid, calculating, for a selected time period, a forecast value for the consumption of power in the microgrid based on said load data, calculating a distribution of power supply to or from said microgrid components based on said calculated forecast value, and controlling said at least one combined consumer and supplier microgrid component to consume or supply power during said selected time period based on said calculated distribution of power supply.

Description

[0001] A METHOD FOR CONTROLLING POWER MANAGEMENT IN A MICROGRID, AND A MICROGRID CONTROLLER PERFORMING SUCH METHOD

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a method for controlling power management in a microgrid located at a project site, and to a microgrid controller for performing the method.

[0004] BACKGROUND

[0005] A microgrid is a network including loads and power sources, and that may operate connected to, and exchange power with a main grid. The microgrid may typically also operate disconnected from the main grid.

[0006] When a microgrid is not connected to the main grid, the power sources of the microgrid supplies power needed for the loads. If the supply and demand of power within the microgrid is not balanced, the microgrid is typically managed by that one or more of the loads will be disconnected, so called load shedding. Methods of load shedding in a grid may be to monitor the frequency, and if a fall of the frequency is detected, perform load shedding.

[0007] Methods of load shedding when the microgrid is disconnected from the main grid, and moves into islanding and the subsequent island operation have been presented. Load shedding may be based on monitoring the power balance and the load shedding is determined prior to islanding in order to speed up the load shedding and stabilize the microgrid quickly if the microgrid becomes disconnected from the main grid.

[0008] It has been suggested to exclude critical loads from disconnection, if possible. Power balance can be monitored to determine a need for load shedding, and the loads may be be shed based on priority. The loads in the microgrid can be labelled as regular loads, sub-critical loads and critical loads. Thereby, a priority for shedding is provided. A method for managing a microgrid may therefore include monitoring the power balance of the microgrid, i.e. the balance between supply and consumption, and shed loads if the consumption exceeds the power supply. The loads are disconnected to minimize the difference between the power supply and the power consumption. Load shedding may be performed when the microgrid is connected to a main grid, as well as in islandic operation. It should be noted that is important to stabilize the microgrid into a new steady state operation during load shedding. Thus, the load shedding need to be performed in order to match the available power and the consumed power at a desired frequency and desired voltage level of the microgrid. The process of disconnecting loads however influences how quickly the microgrid stabilizes. There is a risk that the process of load shedding leads to destabilization when the power flow in the microgrid changes.

[0009] Within mining and construction, power supply is a critical factor. If several power consuming machines (power 50-500 kW) are used simultaneously this may cause the power supply net to drop with power cut as a result. Stop of one or more machines is both time consuming and expensive, and downtime should therefore be avoided as far as possible.

[0010] It is a general object of embodiments herein to provide an improved method for managing a microgrid.

[0011] SUMMARY

[0012] According to a first aspect, a method for power management in a microgrid located at a mining or a construction project site is provided. The microgrid is detachably connected to an external power grid and have a plurality of interconnected microgrid components including one or more of power consumers and power suppliers. At least one microgrid component is a combined power consumer and power supplier. The method comprises receiving, from the microgrid components, load data representing a current, anticipated and / or planned load on the microgrid, calculating, for a selected time period, a forecast value for the consumption of power in the microgrid based on the load data, calculating a distribution of power supply to or from the microgrid components based on the calculated forecast value, and controlling the at least one combined consumer and supplier microgrid component to consume or supply power during the selected time period based on the calculated distribution of power supply. Receiving load data may further comprise receiving a threshold value for load on the external power grid. Controlling may be based on a selectable value for the level of power consumption for the microgrid. Methods herein may further comprise receiving current and historical power data associated with the power sources, and, based on the received load data and the received power data, calculating, for a predetermined time period, a predicted power supply capacity based in the received current and historical power data, and determining operational state for each respective of the plurality of microgrid components based on the predicted power supply.

[0013] In methods herein, receiving load data may comprise receiving a load profile for each respective plurality of microgrid components. Receiving load data may comprise receiving current and historical power consumption for each respective plurality of microgrid components. Methods herein may further comprise predicting a future power consumption for each of the plurality of microgrid components, based on the received load data.

[0014] Methods herein may further comprise monitoring the power balance in the microgrid, determining a need for power supply in view of the power balance and selecting, based on the determining, at least one microgrid component to supply power. Thereby the power in the microgrid is balanced.

[0015] In methods herein, the selected microgrid component may supply active power to the microgrid. Thereby the active power in the microgrid is balanced. In other methods herein, the microgrid is an AC-net, and the selected microgrid component may supply reactive power to the microgrid. Thereby the reactive power in the microgrid is balanced.

[0016] Methods herein may further comprise selecting at least one microgrid component as prioritized for receiving power in relation to at least one other microgrid component of lower priority. Further, in methods herein a microgrid controller may communicate with an autonomous site control software operating several machines and a fleet scheduling system. The communication may be unidirectional or bidirectional.

[0017] In methods herein, the at least one combined consumer and supplier microgrid component may supply power by regenerative breaking. According to another aspect, a microgrid controller for controlling power management in a microgrid located at a project site is provided. The microgrid controller is arranged to perform methods disclosed herein. The microgrid controller may be arranged to communicate with at least one of a remote monitoring system and a remote energy management system. The microgrid controller may be comprised in the microgrid. The microgrid controller may further be arranged to control a microgrid comprising at least one of a battery management system, a power conversion system, a HVAC system, a solar power generator, a wind power generator, a hydro power generator, a wave generator or a diesel generator.

[0018] According to yet another aspect, a computer program product for a microgrid is provided. The computer program product is storable on a computer medium, and, when executed by a microgrid controller, enables the microgrid controller to perform the methods disclosed herein.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Further objects and advantages of, and features of embodiments herein will be apparent from the following description, with reference to the appended drawing, where Fig. 1 is a block diagram.

[0021] DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

[0022] The present disclosure is developed in more detail below referring to the appended drawing which shows an example of an embodiment. The disclosure should not be viewed as limited to the described examples of embodiments. Like numbers refer to like elements throughout the description.

[0023] The terminology used herein is for the purpose of describing particular aspects of the disclosure only and is not intended to limit the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0024] Fig. 1 shows a block diagram for a microgrid located at a mining or a construction project site as disclosed herein. The microgrid 1 is detachably connected to an external power grid 2 and have a plurality of interconnected microgrid components 3 including one or more of power consumers and power suppliers. At least one microgrid component 3a is a combined power consumer and power supplier.

[0025] Such a combined consumer and supplier microgrid component may for example supply power by regenerative breaking. For example, heavy machines on such a project site may be driven by an electrical motor and may work up and down in a slope, where a lot of power is consumed when moving upwards, and regenerative breaking may be used when moving downwards. Other means for supplying power may be by an internal battery, or by an associated or integrated diesel generator, or by solar panels.

[0026] The microgrid is controlled by methods for power management in the microgrid 1. The method comprises receiving, from the microgrid components 3, load data representing a current, anticipated and / or planned load on the microgrid 1 , calculating, for a selected time period, a forecast value for the consumption of power in the microgrid 1 based on the load data. The method calculates a distribution of power supply to or from the microgrid components 3 based on the calculated forecast value, and control the combined consumers and supplier microgrid component 3a to consume or supply power during the selected time period based on the calculated distribution of power supply.

[0027] Further, the microgrid 1 is associated with a microgrid controller 4 for controlling power management in the microgrid located at a project site. The microgrid 1 may further comprise a battery management system, a power conversion system, a HVAC system, a solar power generator, a wind power generator, a hydro power generator, a wave generator or a diesel generator. Some of the comprised microgrid components may be pure consumers, or pure generators, or a combination thereof as already described above. Depending on the load in the microgrid the components may be controlled in an operating state optimising the operation from an economical and time efficient perspective. For example or consumers or combined cosnumers and suppliers may be operated at full power when the electricity price provided by the external net 2 is low. On the other hand, the power supplied by the external net 2 may be minimised when the electricity price is high.

[0028] Receiving load data may further comprise receiving a threshold value for load on the external power grid 2. Thereby, the microgrid 1 may be controlled in a manner taken into account the current status of the external power grid 2. The external power grid 2 may for example have a heavy load from other consumers and by controlling the microgrid a possible downtime of the external net 2 may be avoided. The threshold may as well taken into account present pricing and other factors, for example if the external net 2 is able to deliver “green” power, thus, power generated optimised from a CO2 perspective.

[0029] Thus, controlling may be based on a selectable value for the level of power consumption for the microgrid 1 in relation to a plurality of factors. Factors that may be taken into account may for example be scheduled project time lines and / or drilling plans, project delivery dates, available machines and, if needed, available operators.

[0030] Further, current and historical power data associated with the power sources available may be received and taken into account. Based on received load data and received power data, a calculation for a predetermined time period for a predicted power supply capacity can be performed based on the received current and historical power data. Determination of operational state for each respective of the plurality of microgrid components may be based on the predicted power supply. Thereby, the microgrid components 3 can be controlled in an optimal way. For example, a component may be a working machine on low load which may for example be a drilling rig between two drilling cycles, such a component may be set to supply power to other microgrid components during the low load period. As a start, a typical load profile for each respective plurality of microgrid components may be achieved. The load profile may be adjusted or adapted depending on the local conditions on site and what tasks that is to be performed. Receiving load data may comprise receiving current and historical power consumption for each respective plurality of microgrid components, and a predicted future power consumption for each of the plurality of microgrid components may be performed, based on the received load data. Such predicted power consumption may take different factors into account like typical work cycles for such a site, or local specified factors like type of bedrock for a drilling rig to drill in.

[0031] Further, monitoring of the power balance in the microgrid may be performed, and determining a need for power supply in view of the power balance and selecting, based on the determining, at least one microgrid component to supply power. By actively selecting components to act as concumers or suppliers, or components to be prioritized, exchanged or disconnected from the microgrid 1 , the power in the microgrid can be balanced. The selected microgrid component may supply active power to the microgrid. Thereby the active power in the microgrid can be balanced. Alternatively or as a complement, if the microgrid is an AC-net, the selected microgrid component may supply reactive power to the microgrid. Thereby the reactive power in the microgrid is balanced.

[0032] By selecting microgrid components as prioritized for receiving power in relation to at least one other microgrid component of lower priority, the microgrid 1 can be controlled in an efficient way. A component may be prioritized for example in order to meet an urgent dead line, or to comply with available machines and / or operators. Further, in methods herein a microgrid controller may communicate with an autonomous site control software operating several machines and a fleet scheduling system. The communication may be unidirectional or bidirectional.

[0033] Methods herein are performed by a microgrid controller 4. The microgrid controller 4 may be arranged to communicate with at least one of a remote monitoring system and a remote energy management system. The microgrid controller 4 may be comprised in the microgrid 4, or may be located outside of the microgrid 1 . The microgrid controller 4 may further be arranged to control a microgrid comprising at least one of a battery management system, a power conversion system, a HVAC system, a solar power generator, a wind power generator, a hydro power generator, a wave generator or a diesel generator.

[0034] Further, a computer program product for a microgrid 1 is provided. The computer program product is storable on a computer medium, and, when executed by a microgrid controller, enables the microgrid controller to perform the methods disclosed herein.

[0035] The above aspects, accompanying claims, and / or examples disclosed herein above and later below may be suitably combined with each other as would be apparent to anyone of ordinary skill in the art. The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. It is contemplated that various alternate embodiments and / or modifications to the present embodiments, whether explicitly described or implied herein, are possible in the light of the disclosure.

[0036] Accordingly, the scope is defined only by the accompanying patent claims.

Claims

CLAIMS1. A method for power management in a microgrid (1 ) located at a mining or a construction project site, the microgrid (1 ) being permanently or detachably connected to an external power grid (2) and having a plurality of interconnected microgrid components (3) including one or more of power consumers and power suppliers, wherein at least one microgrid component is a combined power consumer and power supplier (3a), the method comprising:- receiving, from said microgrid components (3), load data representing a current, anticipated and / or planned load on the microgrid (1 );- calculating, for a selected time period, a forecast value for the consumption of power in the microgrid (1 ) based on said load data;- calculating a distribution of power supply to or from said microgrid components (3) based on said calculated forecast value, and- controlling said at least one combined consumer and supplier microgrid component (3d) to consume or supply power during said selected time period based on said calculated distribution of power supply.

2. The method according to the preceding claim, wherein receiving load data further comprises receiving a threshold value for load on the external power grid. »tanken har ar att man ska halla koll pa att man inte sanker det externa natet3. The method according to any of the preceding claims, wherein controlling further is based on a selectable value for the level of power consumption for the microgrid (1 ). »tanken ar att man kan valja hur mycket “kram” microgrid ska ta fran det externa natet, billig el = mycket, dyr el = litet4. The method according to any of the preceding claims, further comprising receiving current and historical power data associated with said power sources; and, based on the received load data and the received power data,- calculating, for a predetermined time period, a predicted power supply capacity based in the received current and historical power data, and- determining operational state for each respective of the plurality of microgrid components (3) based on the predicted power supply.

5. The method (1 ) according to any of the preceding claims, wherein receiving load data comprises receiving a load profile for each respective plurality of microgrid components (3).

6. The method (1 ) according to any of the preceding claims, wherein receiving load data comprises receiving current and historical power consumption for each respective plurality of microgrid components (3).

7. The method (1 ) according any of to the preceding claims, further comprising predicting a future power consumption for each of said plurality of microgrid components (xx, xx), based on said received load data.

8. The method according to any of the preceding claims, further comprising- monitoring (xx) the power balance in the microgrid (1 );- determining (xx) a need for power supply in view of the power balance; and- selecting (xx), based on the determining, at least one microgrid component (xx) to supply power, whereby the power in the microgrid is balanced.

9. The method according to the preceding claim, wherein the selected microgrid component supply active power to the microgrid, whereby the active power in the microgrid (1 ) is balanced.

10. The method according to claim 8, wherein said microgrid is an AC-net, and wherein the selected microgrid component supply reactive power to the microgrid, whereby the reactive power in the microgrid (1 ) is balanced.11 . The method according to any of the preceding claims, the method further comprising- selecting at least one microgrid component as prioritized for receiving power in relation to at least one other microgrid component of lower priority.

12. The method according to any of the preceding claims, wherein a microgrid controller (4) communicates with an autonomous site control software operating several machines and a fleet scheduling system.

13. The method according to the preceding claims, wherein said communication is unidirectional.

14. The method according to claim 12, wherein said communication is bidirectional.

15. The method according to any of the preceding claims, wherein said at least one combined consumer and supplier microgrid (xx) component supply power by regenerative breaking.

16. A microgrid controller (4) for controlling power management in a microgrid (1 ) located at a project site, wherein said microgrid controller is arranged to perform the methods according to any of claims 1 -15.

17. The microgrid controller (4) according to the preceding claim, wherein the microgrid controller is arranged to communicate with at least one of a remote monitoring system and a remote energy management system.

18. The microgrid controller (4) according to any of claims 16 or 17, wherein the microgrid controller is comprised in the microgrid.

19. The microgrid controller (4) according to any of claims 16 - 18, further arranged to control a microgrid (1 ) comprising at least one of a battery management system, a power conversion system, a HVAC system, a solar power generator, a wind power generator, a hydro power generator, a wave generator or a diesel generator.

20. A computer program product for a microgrid (1 ), which computer program product is storable on a computer medium, and which computer program product when executed by a microgrid controller (4), enables the microgrid controller (4) to perform the method of any of claims 1 to 15.

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