ABB Schweiz AG
[2019] APO 27
•7 June 2019
IP AUSTRALIA
AUSTRALIAN PATENT OFFICE
ABB Schweiz AG [2019] APO 27
Patent Application: 2014410506
Title:Control of a Microgrid
Patent Applicant: ABB Schweiz AG
Delegate: M. G. Kraefft
Decision Date: 7 June 2019
Hearing Date: Written submissions filed on 23 April 2019
Catchwords: PATENTS – section 45 – examiner’s objection – whether there is inventive step – microgrid with multiple points of common coupling allowing power flows between microgrid and other power grids – formulation of problem in art – documented problems in specification not based on information available as common general knowledge or under subsection 7(3) – control of second power flow in microgrid in dependence on changes in first power flow not established to have been obvious – application to be accepted.
Representation: Patent attorney for the applicant: Griffith Hack
IP AUSTRALIA
AUSTRALIAN PATENT OFFICE
Patent Application: 2014410506
Title:Control of a Microgrid
Patent Applicant: ABB Schweiz AG
Date of Decision: 7 June 2019
DECISION
The claimed invention has an inventive step.
I direct that the application be accepted.
REASONS FOR DECISION
BACKGROUND
ABB Technology Ltd filed patent application 2014410506 (“the application”) under the Patent Cooperation Treaty (“PCT”) on 4 November 2014 (“the priority date”). Subsequently the name of the applicant was changed to ABB Schweiz AG (“the applicant”).
The application has been subjected to three examination reports. The first two reports contained objections that a number of the claims of the specification lacked novelty and/or an inventive step. While the applicant filed proposed amendments to the specification and filed responsive submissions, the examiner maintained an inventive step objection in the third report.
The applicant subsequently requested to be heard.
The final date for acceptance of the application was 9 February 2019. Nonetheless patent sub-regulation 13.4(1)(g) may be available to extend the time for gaining acceptance to 3 months from the date of the present decision.
SPECIFICATION
The specification describes the alleged invention as relating to a control method in an electrical microgrid having multiple points of common coupling (“PCCs”) with one or several other electrical power grid(s).
As background, the specification describes a microgrid as a localised grouping of electricity generation, energy storage and loads that normally operates connected to a traditional, centralised grid, that is a macro-grid, via a PCC. This single PCC with the macro-grid may be disconnected. This is known as islanding the microgrid.
Microgrids are part of a structure aimed at producing electrical power locally from many small energy sources, such as distributed generators (“DGs”). Examples of distributed power generation systems may be those based on renewable energy resources, such as wind turbines and solar panel systems. In a microgrid, a DG is connected via a converter which controls the output of the DG, that is, the current injected into the microgrid.
When in grid connected mode, that is, connected to the macro-grid, a microgrid supplies the optimised or maximum power outputs from the connected DG sites and the rest of the power is supplied by the macro-grid. The microgrid is connected to the macro-grid at a PCC through a controllable switch. During grid fault, the grid connection is lost and the microgrid is islanded.
As mentioned above, a microgrid may have more than one PCC. In that case, power transfer may still occur over one of the PCCs if the microgrid is islanded at another of the PCCs. Typically, the power transfer will then increase substantially over the PCC which is still connected to compensate for the islanding. Similarly, if an islanded PCC is reconnected, then the power transfer over the other, already connected, PCC will typically drop substantially.
Using a plurality of PCCs provides redundancy and also flexibility in enabling multiple power grids, including the microgrid, to be connected to each other and for transferring power between them. As proposed to be amended, the specification mentions, on the other hand, that the inventors have realised that using multiple PCCs introduces additional challenges for the control of the microgrid. For instance, the power flow over a second PCC is affected by the power flow over a first PCC. This is even more pronounced if the microgrid is islanded or resynchronised at the first PCC, resulting in a transient power flow at the second PCC. This may lead to imbalances in the microgrid, and possibly also in the power grid with which the microgrid is connected via the second PCC, especially if it is a weak grid or another microgrid.
The specification, as proposed to be amended, ends with 13 claims. Claims 1, 11 and 12 are independent claims. Claim 13 is an appended claim to a computer program product. These claims may be found at Annex A at the end of this decision.
APPLICABLE LAW
The application is governed by the Patents Act 1990 (“the Act”) as amended by the Intellectual Property Laws Amendment (Raising the Bar) Act 2012 (“the Raising the Bar Act”). Amendments to Sections 7, 40 and 49 of the Act apply to the present case as a consequence of Schedule 1, items 55(1)(d) and 55(4)(a), and Schedule 6, item 133(7)(d), of the Raising the Bar Act. The application was filed after 15 April 2013.
Sub-section 18(1) of the Patents Act 1990 relevantly provides that:-
(1)Subject to subsection (2), an invention is a patentable invention for the purposes of a standard patent if the invention, so far as claimed in any claim: …
(b) when compared with the prior art base as it existed before the priority date of that claim: …
(ii) involves an inventive step.
The standard of proof that applies is the balance of probabilities (subsection 49(1)). I must accept the application if satisfied on the balance of probabilities that the application complies with the Act. If I am not so satisfied, then I can refuse the application.
INVENTIVE STEP LAW
Subsection 7(2) of the Act states that an invention is taken to involve an inventive step unless it would have been obvious to a person skilled in the relevant art in the light of the common general knowledge as it existed before the priority date of the relevant claim, whether that knowledge is considered separately or together with information mentioned in subsection (3).
Subsection 7(3) states the information for the purposes of subsection (2) is any single piece of prior art information, or a combination of any 2 or more pieces of prior art information that the skilled person mentioned in subsection (2) could, before the priority date, be reasonably expected to have combined.
A number of decisions provide guidance as to the test for whether an invention would have been obvious at the relevant time. In Wellcome Foundation Ltd v VR Laboratories (Aust.) Pty Ltd,
[1981] HCA 12, 148 CLR 262 at 286 [45], Aickin J stated:
"The test is whether the hypothetical addressee faced with the same problem would have taken as a matter of routine whatever steps might have led from the prior art to the invention, whether they be the steps of the inventor or not."
The High Court in Aktiebolaget Hässle v Alphapharm Pty Ltd, [2002] HCA 59, (2002) 56 IPR 129 at [50] – [53] (“Alphapharm”), appeared to approve of the Wellcome test. In discussing what was meant by a matter of routine the High Court noted and accepted an affinity with the approach in Olin Mathieson Chemical Corporation v Biorex Laboratories Ltd, (1970) 87 RPC 157, of whether the person skilled in the art would directly be led as a matter of course to try what was claimed in the expectation that it might well produce a useful alternative.
In AstraZeneca AB v Apotex Pty Ltd, [2014] FCAFC 99, the court held at [203] that in formulating the problem it is not permissible to incorporate information that is not available to the person skilled in the art either as common general knowledge or information available under subsection 7(3).
It may be noted that the above cases proceed on a premise that there was a problem to be solved. Moreover it seems clear from Alphapharm that establishing that something was worthwhile or obvious to try is not sufficient to support a finding of lack of inventive step, noting also at [34] that the phrase “worthwhile to try” is not readily understood as synonymous with “obvious”. At [58]:-
“The tracing of a course of action which was complex and detailed, as well as laborious, with a good deal of trial and error, with dead ends and the retracing of steps is not the taking of routine steps to which the hypothetical formulator was taken as a matter of course.”
Where the invention lies in a combination of integers, the question is not whether each individual integer was obvious but rather whether the combination as a whole was obvious when compared to the prior art base. In Alphapharm at [41], the High Court stated:
“The claim is for a combination, the interaction between the integers of which is the essential requirement for the presence of an inventive step. It is the selection of the integers out of ‘perhaps many possibilities’ which must be shown by Alphapharm to be obvious, bearing in mind that the selection of the integers in which the invention lies can be expected to be a process necessarily involving rejection of other possible integers.”
In Lockwood Security Products Pty Ltd v Doric Products Pty Ltd [No. 2], [2007] HCA 21, (2007) 235 ALR 202, general principles regarded to be of continuing relevance, at [50] – [52], were that “obvious” means “very plain”, a scintilla of invention remains sufficient to support the validity of a patent, there must be some difficulty overcome, some barrier crossed, and an invention must be beyond the skill of the calling.
THIRD EXAMINATION REPORT
This report indicates that all of the claims of the application lack an inventive step when compared with patent application US 20130187454 to Timbus et al (“D1”). The relevant content of the report is as follows:-
“The examiner appreciates for (sic) highlighting the features of the process of identifying an islanding event, controlling the power flow based on the obtained information. The examiner acknowledges that the features of controlling the second power flow based on the obtained information in relation to change/s in the first power flow has not been disclosed in the raised prior art.
The examiner refers that the raised prior art D1 is directed towards a method for detecting islanding conditions in an electric power network including a plurality of sub-networks in order to provide control mode/s (e.g. connect, disconnect, switching, SCADA) in relation to power generators/grids/microgrids (see – D1 – the abstract, figure 3, paragraphs [0009], [0017], [0026], [0051]-[0053] for details).
Claim 1 lacks an inventive step when compared with the prior art document D1.
D1 discloses a control method performed in a microgrid (figure 3, item 13, paragraphs [0063]-[0072]) comprising:
at least one electrical power source configured for injecting electrical power into the microgrid (figure 3, paragraphs [0005], paragraphs [0063]-[0072]);
a first point of common coupling, PCC, (figure 3, item 18) configured for allowing a first power flow between the microgrid and a first power grid (figure 3, item 15, refer to the Table 1 under paragraph [0068] which shows the non-islanding condition in relation to Switch 18 when the Switch 18 has a closed position labelled as 1, paragraphs [0063]-[0072]);
and a second PCC configured for allowing a second power flow between the microgrid and a second power grid (figure 3, item 14, refer to the Table 1 under paragraph [0068] which shows the non-islanding condition in relation to switches 20, 25, 18, paragraphs [0063]-[0072];
the method comprising:
obtaining information about a change in the first power flow (power flow (non-islanding) logic as described in TABLE 1 under paragraph [0068], refer to paragraphs [0063]-[0072] for detailed logic and associated power electronic units).
D1 does not disclose the feature of controlling the second power flow based on the obtained information in relation to change/s in the first power flow. However the feature of controlling a power flow based on the acquired information about the change/s in other (second) power flow is merely a matter of design choice that would be obvious to a PSA in relation to power networks/transmission having plural grids/microgrids and therefore cannot contribute in providing a patentable subject matter.
A similar reasoning as per claim 1 is applied to the invention defined in claims 11 and 12.
Furthermore, appended claims 2-10 and 13 add only features that are either disclosed in the above cited document(s) or are common general knowledge in the art/mere design choices/etc. and which therefore cannot contribute to providing an inventive step. For example, the features of claims 2 and 8 are disclosed in D1 (see – figures 2-3, items 13, 14, 15, paragraphs [0063]-[0072]).” (emphasis throughout in the original)
SUBMISSIONS
After discussing the background to the invention, the nature of the claimed invention and what was meant by control in the context of the specification, the applicant focused its attention on D1. The applicant acknowledged that D1 considered a microgrid similar to the structural elements of the claimed invention. While D1 related to the detection of islanding conditions and controlling one or more electrical units within a microgrid in which islanding had been detected, the applicant submitted that the control described in D1 was not within the scope of controlling a power flow through a second PCC as claimed in the present case.
More specifically, the applicant indicated that D1 related to a different problem to that of the present invention. That is, D1 is concerned with detecting islanding conditions within a microgrid and shutting down power generating units within that microgrid and/or changing a control mode of the power units from power injection to voltage and frequency control in case the identified island is permitted, when islanding occurs. By contrast, the applicant stated that the claimed invention is not directed towards a specific method for detecting islanding conditions. Instead, the invention is concerned with controlling power flow at a second PCC based on information about power flow at a first PCC.
The applicant accepted that power flow at certain switches in D1 may be affected by shutting down or changing the mode of power units when islanding is detected. On the other hand, the applicant submitted there was no active step to achieve a desired result and thus the effect on the power flow was not control of the power flow. The applicant thus concluded that D1 failed to disclose any consideration of the power flow at the closed switches and any consequent action arising therefrom.
In respect to the examination report, the applicant took issue with the assertion that the feature of controlling the second power flow, based on the obtained information in relation to changes in the first power flow, is merely a matter of design choice that would be obvious to a person skilled in the art in relation to power networks or transmissions having plural grids or microgrids. The applicant submitted the report provided no additional explanation as to the reason that feature was considered obvious. Additionally, the applicant submitted that no reasoning or evidence was put forward as to why such a modification would have formed part of the common general knowledge of the person skilled in the art at the priority date. With reference to D1, the applicant stated there was no disclosure of taking any action relating to power flow between a microgrid and another grid. Thus, rather than being merely a matter of design choice, the applicant concluded there was no reason, based on D1, to design any control of the power flow at the second PCC, let alone a control based on power flow at the first PCC.
DISCUSSION
Whether There is Inventive Step
D1 discloses a method of detecting islanding conditions in an electrical power network. The electrical network may be supplied by a main grid. The electrical power network may be divided into a plurality of sub-networks, wherein the sub-networks include at least one power electrical unit. A power electrical unit can, for instance, be a load or a DG. The sub-networks are separable from each other and from a main grid, supplying the network, by switching devices.
D1 mentions the desirability for DGs to be able to immediately stop power production when islanding conditions are detected. This is for the safety of utility workers and to prevent damage to equipment.
Islanding conditions within some or all of the sub-networks can be determined in a decentralised manner. This can be achieved on the basis of analysing topological information of the sub-networks. The topological information may include the operational state of at least one switching device in a sub-network. Moreover, the topological information may include details of the structure of the electrical network and/or sub-network. The structure can, for instance, be represented by a truth table. The truth table can indicate which combinations of switching devices’ operational states produce islanding conditions within a particular sub-network. Separate detecting means of the operational states of switching devices can be used for each sub-network. Finally, a signal resulting in disconnection or a control mode change can be sent to the power electrical units of an island in the sub-network on the basis of the islanding conditions determined by the detecting means.
In relating the disclosure of D1 to the present invention as claimed, it is convenient to refer to Figure 3 of D1, which is reproduced below.
D1 discloses a method performed in a microgrid (one of sub-networks 13 or 14, say 13). There is at least one electrical power source (e.g a DG within each microgrid 13 or 14, [0064]) configured for injecting electrical power into the microgrid. A first PCC (switching device 18) is configured for allowing a first power flow between microgrid 13 and a first power grid (main grid 15). A second PCC (switching device 20) is configured for allowing a second power flow between the microgrid and a second power grid (microgrid 14). Information about a change in the first power flow may be obtained through an apparatus 10, within substation 16, which may detect islanding conditions in microgrid 13, or in groups 21, 22 and 23 thereof. For instance, islanding conditions may be determined on the basis of the operational status of switching devices 18, 20, 24 and/or 25. A signal resulting in disconnection or a control mode change can be sent to the power electrical units of an island in the sub-network on the basis of the islanding conditions determined by apparatus 10, or by a similar apparatus 11 within substation 17.
The independent claims of the present application further define the step of controlling the second power flow based on the obtained information, that is, information about a change in the first power flow. As indicated above, it may be that the operational status of a second PCC in D1 (20) is monitored. On the other hand, there is no disclosure in D1 that power flow at the second PCC is controlled based on changes in the power flow at the first PCC.
As the present specification indicates though, it may be expected that power flow over a second PCC (say switching device 20) of the microgrid 13 is affected by power flow over a first PCC (say switching device 18). This may also be more pronounced if the microgrid is islanded at the first PCC. On the other hand, the question in the present case is whether, with the disclosure of D1 in mind, it would have been obvious to the relevant person skilled in the art at the relevant time to control the power flow over the second PCC, in some way, if the power flow changed at the first PCC.
While control is generally a relatively broad concept, it may be limited with the understanding that, in the present context, it involves some form of regulating or governing the item to be controlled (Oxford English Dictionary; The specification documents the problems regarding transient power flow at the second PCC if the microgrid is islanded or resynchronised at the first, and the resultant imbalances in the microgrid. In the light of these problems, one could thus suggest it would have naturally been highly desirable to control the second power flow dependent on changes in the first. The specification, at the foot of page 4, mentions this as an objective, particularly for planned islanding or resynchronisation at the first PCC in a multiple PCC microgrid. On the other hand, this is the wrong approach in assessing inventive step. The AstraZeneca case does not permit the formulation of the problem to be based on information not available to the person skilled in the art either as common general knowledge or under subsection 7(3). While the specification acknowledges the prior existence of microgrids with more than one PCC, I have insufficient information before me in this case that such arrangements were common general knowledge at the relevant time, still less that the above-mentioned problems in respect to such arrangements were common general knowledge. In reference to subsection 7(3), D1 is an example of a prior disclosure of a microgrid with more than one PCC. On the other hand, D1 is concerned with detecting islanding conditions and disconnecting islanded DGs. D1 does not appear to consider or address further, more specific problems such as imbalances in the microgrid due to transient power flows at a second PCC when islanding occurs at a first PCC.
On the information before me in the present case, I find that the problems documented in the specification, and that may lead one to desire to control the second power flow as claimed, were not common general knowledge at the relevant time. Similarly, D1 is not directed to addressing such problems. Consequently, I think it cannot be fairly said that the control of the second power flow in dependence on changes in the first power flow, as claimed, was obvious at the relevant time.
I conclude the claimed invention has an inventive step.
CONCLUSION
I have found that the claimed invention has an inventive step.
The application should be accepted.
M. G. Kraefft
Delegate of the Commissioner of PatentsAnnex A
1. A control method performed in a microgrid comprising:
at least one electrical power source configured for injecting electrical power into the microgrid;
a first point of common coupling, PCC, configured for allowing a first power flow between the microgrid and a first power grid; and
a second PCC configured for allowing a second power flow between the microgrid and a second power grid;
the method comprising:
obtaining information about a change in the first power flow; and
controlling the second power flow based on the obtained information.11. A control system configured for a microgrid, which microgrid comprises:
at least one electrical power source configured for injecting electrical power into the microgrid;
a first point of common coupling, PCC, configured for allowing a first power flow between the microgrid and a first power grid; and
a second PCC configured for allowing a second power flow between the microgrid and a second power grid;
the control system being configured for:
obtaining information about a change in the first power flow; and
controlling the second power flow based on the obtained information.12. A microgrid comprising:
at least one electrical power source configured for injecting electrical power into the microgrid;
a first point of common coupling, PCC, configured for allowing a first power flow between the microgrid and a first power grid; and
a second PCC configured for allowing a second power flow between the microgrid and a second power grid; and
a control system being configured for:
obtaining information about a change in the first power flow; and
controlling the second power flow based on the obtained information.13. A computer program product comprising computer-executable components for causing a control system of a microgrid to perform the method of any one of claims 1 to 10 when the computer-executable components are run on processor circuitry comprised in the control system.
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