WO2023001378A1

WO2023001378A1 - Hybrid phase selector

Info

Publication number: WO2023001378A1
Application number: PCT/EP2021/070609
Authority: WO
Inventors: Debrup DAS; Jiuping Pan; Parag Upadhyay
Original assignee: Hitachi Energy Switzerland Ag
Priority date: 2021-07-22
Filing date: 2021-07-22
Publication date: 2023-01-26

Abstract

An apparatus (300) with multiple input power phases and one output power phase and a corresponding method is provided. The apparatus includes: a plurality of input terminals (306) each adapted to be connected to a different power source phase; a plurality of main current paths (312) each connected to an input terminal and the output power phase (314), each main current path having an inductor (308) and a first mechanical switch (310); a plurality of power electronic (PE) paths (318), each connected in parallel with a main current path and connected to an input terminal and the one output power phase and having one or more PE switches (320) and a second mechanical switch (310); and a controller (302) coupled to the first mechanical switch (310) of each main current path (312), the one or more PE switches (320) and the second mechanical switch (310) of each PE path (318).

Description

HYBRID PHASE SELECTOR

TECHNICAL FIELD

[0001] Hie present disclosure relates generally to power phase balancing, and more particularly to methods and related devices supporting phase switchovers.

BACKGROUND

[0002] The primary distribution systems consist of feeders that deliver power from distribution substations to distribution transformers (also referred to as service transformers). Primary distribution systems have voltage classes ranging from 5kV to 35kV, and the most common voltages are between lOkV and 15kV. A distribution feeder may include the main feeder, usually a three-phase, four-wire circuit, and laterals branching from the mains, which may be either three-phase or single-phase circuits as shown in Figure 1. Residential and small commercial customers typically require single-phase power, and industrial and large commercial customers typically require three-phase service. As shown in Figure 1, single-phase loads are served by single-phase distribution transformers connected between one phase of the three- phases and the neutral. Some distribution primaries are three-wire systems (with no neutral) and the laterals branching from the mains may be either three-phase or two-phase circuits. On these systems, single -phase loads are connected phase to phase.

[0003] Phase unbalance is a phenomenon in distribution systems primarily because a high percentage of electricity end users require single-phase power services. Excessive phase current and voltage unbalance may lead to a number of consequences. These consequences include: 1) additional investment costs for substation and circuit upgrade; 2) increased energy losses in the transformers and feeder circuits; 3) power quality issues; 4) nuisance tripping; and 5) damages to induction motors. Historically, the phase unbalance problem was more seasonal, and manual switchover, i.e., moving loads or laterals from the heavily loaded phase to the light phase(s) on an interv al basis was enough and presently still is the common practices of electric utilities. Increasing penetration of single-phase DERs (distributed energy resources) and EV (electric vehicle) charging loads are expected to significantly exacerbate the issue of phase balancing - both in terms of degree of unbalance, as well as frequency of unbalance occurrence. Under such conditions, manual switchover practices will no longer be a sufficient solution. Manual switchover is expensive (can cost hundreds or sometimes thousands of U.S. dollars) as it requires a truck roll (i.e., a utility truck driven by a utility worker that manually performs a switchover) and now it needs to be performed frequently. In operational planning and scheduling, it is a challenge to predict distribution feeder unbalance conditions with adequate accuracy due to high uncertainties of demands and DERs.

[0004] Distribution static synchronous compensator (D-STATCOM) and DERs control D-STATCOM has been used to improve the power quality and dynamic voltage support of the distribution system through reactive power compensation. With individual-phase decoupled PQ control, D-STATCOM also has the capability to transfer active powers among the three phases for balancing the active power flows in the distribution system. However, D- STATCOM solutions may be limited due to high costs and high energy losses, and it may be only considered when multiple operational issues, such as a combination of phase unbalance and poor power quality, need to be addressed. The power injection from inverter interfaced DERs can be controlled to balance the power flows in the distribution system. For three-phase DERs, this solution may require increased inverter ratings in order to inject unbalanced powers into different phases. For single -phase DERs, three-phase inverters are required. In both cases, utility incentives are required to compensate for the costs for increased inverter ratings and control update(s).

[0005] Various switching mechanism have been introduced for rebalancing loads among phases in power distribution systems. One proposed mechanism uses separate phase changeover switches for switching between each pair of phases and switches based on zero phase current detection. Some switching designs need to switch to an intermediate phase when transitioning between two phases which may cause undesirable transients. Another switching mechanism features a shaft and rotatable contacts to selectively connect the load to at least one phase of a multi-phase feeder system wherein semiconductor devices (such as thyristors) are used to maintain the connection with one phase while rotatable contact member is moving between phases.

SUMMARY

[0006] Accordingly, there is an unmet need for automated, cost-effective phase transfer solutions that can achieve greater and flexible phase selectivity for a variety of single phase loads and single-phase laterals in power distribution systems.

According to some embodiments, an apparatus with multiple input power phases and one output power phase is provided. The apparatus includes a plurality of input power terminals each adapted to be connected to a different power source phase. The apparatus further includes a plurality of main current paths each connected to one of the input terminals and the one output power phase, each main current path having an inductor and a first mechanical switch. The apparatus further includes a plurality of power electronic paths, each power electronic path connected in parallel with one of the plurality of main current paths and connected to the one of the input terminals and the one output power phase, each power electronic path comprising one or more power electronic switches and a second mechanical switch. The apparatus further includes a controller communicatively coupled to the first mechanical switch of each of the plurality of main current paths, the one or more power electronic switches and the second mechanical switch of each of the plurality of power electronic paths. The controller is configured to receive a phase switchover command to switch the one output power phase from an initial main current path connected to an initial power source phase to a new main current path connected to a new power source phase or determining that the one output power phase should be switched from the initial main current path to the new main current path; and control the first mechanical switch of the initial main current path, the second mechanical switch and the one or more power electronic switches of an initial power electronic path connected in parallel with the initial main current path, the first mechanical switch of the new main current path and the second mechanical switch and the one or more power electronic switches of a new power electronic path connected in parallel with the new main current path to switch the one output power phase from the initial main current path to the new main current path while reducing disturbances on a load of the one output power phase during changeover from the initial main current path to the new main current path.

[0007] Advantages that may be achieved using the embodiments described herein include automated, cost-effective phase transfer solutions that can achieve greater and flexible phase selectivity for a variety of single-phase loads and single-phase laterals in distribution systems. The main advantages that can be achieved include: be extremely low-cost technology for widespread utility acceptance and adoption; be easily scalable, especially in voltage; be applicable to both four-wire and three-wire distribution systems; and have an installation not requiring changes or rearrangements of distribution transformers and protection devise.

[0008] According to other embodiments, a method by a phase selector apparatus having multiple input power phases and one output power phase, a plurality of main current paths each connected to one of the multiple input power phases and the one output power phase, each main current path having an inductor and a first mechanical switch and a plurality of power electronic paths, each power electronic path connected in parallel with one of the plurality of main current paths and connected to one of the multiple input power phases and the one output power phase, each power electronic path comprising one or more power electronic switches and a second mechanical switch is provided. The method includes receiving a phase switchover command to switch the one output power phase from an initial main current path connected to an initial power source phase to a new main current path connected to a new power source phase or determining that the one output power phase should be switched from the initial main current path to the new main current path. The method includes controlling the first mechanical switch of the initial main current path, the second mechanical switch and the one or more power electronic switches of an initial power electronic path connected in parallel with the initial main current path, the first mechanical switch of the new main current path and the second mechanical switch and the one or more power electronic switches of a new power electronic path connected in parallel with the new main current path to switch the one output power phase from the initial main current path to the new main current path while reducing disturbances on a load of the one output power phase during changeover from the initial main current path to the new main current path.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate certain non-limiting embodiments of inventive concepts. In the drawings:

[0010] Figure 1 is a schematic diagram of a distribution feeder with neutral illustrating connection of single-phase loads;

[0011] Figure 2 is a schematic diagram illustrating example placements of hybrid phase selectors (HPSs) for connecting single-phase loads and single-phase lateral in a distribution feeder according to some embodiments described herein;

[0012] Figure 3 is an illustration of a pole top implementation of the hybrid phase selector (HPS) according to some embodiments described herein;

[0013] Figure 4 is a block diagram illustrating a hybrid phase selector controller according to some embodiments described herein;

[0014] Figure 5 is a schematic diagram of a HPS with two phase inputs according to some embodiments described herein;

[0015] Figure 6A -6C are schematic diagrams illustrating a phase switchover from a phase A to a phase B according to some embodiments described herein;

[0016] Figure 7 is a schematic diagram of a HPS with three phase inputs according to some embodiments described herein;

[0017] Figure 8 is a schematic diagram of a printed circuit board (PCB) based implementation of a two phase electrical path according to some embodiments described herein;

[0018] Figure 9 is a schematic diagram illustrating three example installations of HPS in a distribution feeder with a neutral according to some embodiments described herein; [0019] Figure 10 is a block diagram illustrating a DMS/SCADA communicating with an HPS including to perform a phase switchover in response to detecting a load imbalance according to some embodiments described herein; and

[0020] Figures 11-12 are flowcharts illustrating operations of a HPS according to some embodiments described herein.

DETAILED DESCRIPTION

[0021] Inventive concepts will now be described more fully hereinafter with reference to the accompanying drawings, in which examples of embodiments of inventive concepts are shown. Inventive concepts may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of present inventive concepts to those skilled in the art. It should also be noted that these embodiments are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present/used in another embodiment.

[0022] The following description presents various embodiments of the disclosed subject matter. These embodiments are presented as teaching examples and are not to be construed as limiting the scope of the disclosed subject matter. For example, certain details of the described embodiments may be modified, omitted, or expanded upon without departing from the scope of the described subject matter.

[0023] As previously indicated, phase unbalance is a common phenomenon in distribution systems in many countries like the US primarily because a high percentage of electricity end users require single-phase power services. Increasing penetration of single-phase distributed energy resources (DERs) and electric vehicle (EV) charging loads are expected to significantly exacerbate the issue of phase balancing - both in terms of degree of unbalance, as well as frequency of unbalance occurrence. Presently, utilities may perform seasonal phase switchovers manually, which requires expensive truck rolls and also assumes good match between model predictions & operations.

[0024] A hybrid phase selector (HPS) is provided that in some embodiments is a low-cost solution to mitigate or reduce the issue of distribution system unbalance. The HPS is a multi-phase input, single phase output device that allows: i) a single-phase load to be served from one of the input phases at a given time; and ii) enables a smooth and automated transition of the single-phase load from a first input phase to a second input phase.

[0025] It is recognized that a viable solution for the problem of automated phase transfer must have the following features for many utility applications: 1. Extremely low-cost for widespread utility acceptance and adoption.

2. Easily scalable, especially in voltage.

[0026] The following assumptions are made in terms of requirements in order to achieve a low-cost, easily scalable solution:

1. Product cost is nominal and less compared with manual switchover operational cost.

2. Target voltage range 5—15 kV, target kVA rating: 167 kVA or less. a. Common distribution feeder voltages in US are 5 to ~15kV, and the most common voltages are 10 to ~15kV (US, EU and CN, etc.) b. Max rating of pole top distribution transformers is 167 kVA.

3. Proposed solution to work outdoor (e.g. pole mounted, underground, etc.).

4. Additional auxiliary power may not be available.

5. It should be connectable to DMS / SCADA.

[0027] The HPS is in its most basic form is a transfer switch that selects which input phase will power the single-phase output. Figure 2 illustrates example placements of an HPS in a distribution system. Figure 2 shows placements of HPS in a distribution system as indicated by the dashed arrows - (1) at the junction 200 of a single-phase lateral and three-phase feeder main and (2) directly serving a single-phase load at 202, 204. Figure 3 illustrates a possible pole-top implementation of the HPS 300 that selects the input between, for example, Phases A and B from a three-phase feeder circuit. The HPS 300 can be remotely controlled by utility distribution management system or substation automation system via a wired and/or a wireless communication connection.

[0028] An HPS needs to be a high reliability, low-loss, low-cost device. To ensure high-reliability and low -loss under steady state conditions, a hybrid switch topology is selected. As shown in Figure 2, the main current path 206 (also referred to as a mechanical path herein) has a mechanical switch, and does not have any pow¾r electronics. A parallel power electronics branch 208 is provided which is only activated during a transition from one phase to another phase.

[0029] A HPS controller 302 that is part of the HPS 300 is illustrated in Figure 4.

The HPS controller is configured to provide wired or wireless communication according to embodiments. As shown, the HPS controller 302 may include an antenna 407, and transceiver circuitry 401 (also referred to as a transceiver) including a transmitter and a receiver configured to provide uplink and dow nlink radio communications with a base station(s) of a radio access network in communication with the DMS/SCADA (distribution management system/ supervisory control and data acquisition). The HPS controller 302 may also include processing circuitry 403 (also referred to as a processor) coupled to the transceiver circuitry, and memory circuitry 405 (also referred to as memory ) coupled to the processing circuitry_'. The memory' circuitry' 405 may include computer readable program code that when executed by the processing circuitry 403 causes the processing circuitry to perform operations according to embodiments disclosed herein. According to other embodiments, processing circuitry 403 may be defined to include memory so that separate memory circuitry is not required. The HPS controller 320 may also include an interface (such as a user interface) coupled with processing circuitry 403.

[0030] As discussed herein, operations of the HPS controller 302 may be performed by processing circuitry 403 and/or transceiver circuitry 401. For example, processing circuitry 403 may control transceiver circuitry 401 to transmit communications through transceiver circuitry' 401 over a radio interface to a radio access network node (also referred to as a base station) and/or to receive communications through transceiver circuitry 401 from a RAN node over a radio interface. Moreover, modules may be stored in memory' circuitry 405, and these modules may provide instructions so that when instructions of a module are executed by processing circuitry 403, processing circuitry 403 performs respective operations (e.g., operations discussed below with respect to embodiments relating to HPS controllers).

[0031] Figure 5 illustrates a two phase hybrid phase selector power stage 304 where the normal current path is through one of the phases A or B. In Figure 5, phase A is the current phase being used where the normal current path is through input power terminal 306, inductor LA 308 and relay SA 310 of the mechanical path A (i.e., main current path A) 312 and output through output power phase 314 and fuse 316. When phase B is the current phase being used, the normal current path is through input power terminal 306 for phase B, inductor LB 308, and relay SB 310 of the mechanical path B 312, and output through output power phase 314 and fuse 316 The input power terminal 306 may be any type of connection to hold a phase connection, including a threaded connection, a quick connector, etc. The HPS controller 302 controls the relays 310 (relay SA and relay SB in the mechanical paths 312, the relays PA and PB of the power electronic paths 318), and the power electronic switches 320 (each power electronic switch 320 can comprise one or more switches, denoted as PE Ai to PE AN for phase A and PE Bi to PE BN for phase B) in the power electronic paths 322 as illustrated by the dashed lines. Specifically, control line 500 is used to control relay SA 310. Control line 502 is used to control power electronic switches PA Ai to PE AN. Control line 504 is used to control relay PA 310. Control line 506 is used to control power electronic switches PA Bi to PE BN. Control line 508 is used to control relay PB 310. Control line 510 is used to control relay SB 310. In some embodiments, the HPS controller 302 receives a command from DMS/SCADA 500 to switch from an initial phase to a new phase. The initial phase is the phase presently providing power to the load via the output power phase 308. The command may be sent from DMS/SCADA 512 via a wired and/or a wireless communication network. In other embodiments, the HOPS controller 302 determines that the output power phase 308 should be switched from the initial phase to a new phase. The determination may be based on load conditions, power quality of the phases, etc.

[0032] Figures 6A to 6C illustrate the steps to switch from an initial phase to a new phase (e.g., from phase A to phase B) when the HPS 300 is connected to two phases. In Figures 6A to 6C, switches and relays that are energized are shaded darker (e.g. near black shading) than switches and relays that are not energized (e.g., light gray) Normally current flows through the mechanical path - MechPath_A or MechPath_B (i.e., main current path A or main current path B) depending on which phase is selected. Hence during normal operation, the current flows through the inductor LA and series relay SA in MechPath_A as shown in illustration 1 of Figure 6A. To execute a phase switchover command, the parallel power electronics path PE_Path_A is activated by the FIPS controller 302 switching the parallel relay PA ON as shown in illustration 2, followed by activating the power electronic switches PE Ai through PE AN as shown in illustration 3. Due to the impedance of the inductance LA, most of the current flows through PE_Path_A. Thus, the current magnitude of Itc_H2 is greater than the current magnitude of ITX_HI. Hence the series relay SA can be switched OFF by the HPS controller 302 as shown in illustration 4 (see Figure 6B) with minimal impact on the relay life.

[0033] The PE Path A is switched OFF by the HPS controller 302 switching off power electronic switches PE_A at a current zero crossing as shown in illustration 5. Once the power electronic switches PE_A are switched off, series relays PA may be switched off. After a brief delay (e.g., 10 us), the path PE_Path_B is activated by HPS controller 302 as shown in illustration 6 where current ITX H flows in PE_Path B when power electronic switches PE Bi through PE BN and series relay PB. MechPath_B is then turned on by the HPS controller 302 turning series relay SB on as shown in illustration 7 (see Figure 6C) where current flows in both MechPath_B and PE_Path_B as illustrated by ITX HI and ITXJE· Finally, the current is fully commutated to the MechPath_B by the HPS controller 302 switching OFF PE_Path_B as shown in illustrations 8 and 9.

[0034] Figure 7 illustrates a HPS 300 having three phases according to some embodiments where the HPS controller controls the relays and power electronic switches as illustrated by the dashed lines. The components of the paths are the same as the components of the paths of Figure 5

[0035] HPS - Design Choices [0036] To ensure low-cost implementation of the HPS, a printed circuit board (PCB) based approach can be taken. This approach would allow low-cost, high-volume production. Additionally, it is identified that the current rating of the HPS is less than 50 A (167 kYA, 5 kV = 34 A). Thus, the strategy of using low-cost discrete thyristors is adopted. These discrete devices are typically rated 1200 V, 50 - 100 A. For example, part number TYN60K-1400T is rated 1200 V, 90 A. One of the main technical challenge will be voltage scaling, i.e., to ensure proper series operation of such devices in order to realize a 5 - 15 kV switch. The mechanical relays PA, PB, RA and RB are also important components. To ensure low overall cost, use of commercial-off-the-shelf (COTS) components are recommended. Example parts include Kilovac KC-18 (15 kV, 30 A) or similar products.

[0037] Voltage Scalability and Auxiliary Power Supply Considerations

[0038] The voltage scaling and auxiliary power challenge can be handled by the printed circuit board, PCB, mounted power electronic switch arrangement 800 shown in Figure 8. Each of the PCBs 802 may have one or more sets of anti-parallel SCRs 804 in series with at least two power terminals (806, 808) that is controlled by gate driver circuitry 810. The gate driver circuitry 810 is connected to a control terminal (812) that receives control commands to turn the SCRs 804 on. Each of the PCBs 800 can handle a certain amount of terminal voltage, say 3-5 kV. For different system voltages a suitable number of PCBs are stacked in series. The auxiliary power 814 is derived through an auxiliary transformer Aux PT 818. The secondary of this transformer forms a current loop, which is indicated by the gray line 820 in Figure 8. The secondary current in this loop may be limited by a resistor (not shown). Individual PCBs derive their auxiliary power through a current transformer 816 through which this secondary current loop is passed. This allows each PCB 800 to be isolated from each other, and the SCRs essentially “float” at the line voltage.

[0039] An envisioned product in some embodiments is expected to be in a price sensitive category and many of the inventive steps described herein are taken to address that [0040] Figure 9 illustrates three example installations of the HPS 300 in a distribution feeder with neutral. These examples are:

• HPS 1 : connecting a single-phase load to one phase of the main feeder, either Phase B or Phase C.

• HPS2 (a three phase HPS): connecting a single-phase lateral to one phase of the main feeder, either Phase A or Phase B or phase C.

• HPS3 : connecting a single-phase load to two phases of the three-phase lateral, such as either Phases A and B, or Phases A and C. [0041] The HPS 300 with two phase inputs would be the base design which is applicable in both four-wire distribution systems (including neutral) and three-wire distribution systems (without neutral). Considering diversified load profiles, the deployment of HPS 300 needs to have different phase connection schemes for sufficient flexibility moving loads from the heavily loaded phase to the light phase(s). This can be determined based on historical and projected loading conditions of different phases of the feeder circuits. The design with three phase inputs has higher flexibility than the base design especially for use in the four-wire distribution systems but incurs increased cost and complexity due to the additional phase input. The HPS 300 has communication capability with the utility DMS/SCADA and Substation Automation System via wired and/or wireless networks and thus can be remotely controlled in real-time to mitigate unbalance and improve system operational efficiency.

[0042] Figure 10 illustrates the HPS 300 being an extendable aspect of a DMS/SCADA system. In the DMS/SCADA system of Figure 10, the DMS/SCADA 512 monitors the phases of the system, detects load imbalances, determines which loads to switch phases, and instructs the HPS controller 302 to control the HPS power stage 304 to switch phases as specified in the instructions to the HPS controller 302. THE DMS/SCADA 512 may use one or more intelligent electronic devices (IEDs) as part of substation automation (SA) at a substation of a utility network as part of distribution automation (DA). In such scenarios, an IED may monitor phases, detect imbalances and provide instructions to an FIPS 300 via wired or wireless communication to perform a phase switchover. The FIPS 300 may provide an indication of the present phase that is energizing the output power phase via wired or wireless communication.

[0043] In the description that follows, operations of the HPS controller 302 (implemented using the structure of the block diagram of Figure 4) will now be discussed with reference to the flow chart of Figure 11 according to some embodiments of inventive concepts. For example, modules may be stored in memory 405 of Figure 4, and these modules may provide instructions so that when the instructions of a module are executed by respective communication device processing circuitry 403, processing circuitry 403 performs respective operations of the flow chart.

[0044] Turning to Figure 11, in block 1101, the processing circuitry 403 receives a phase switchover command having an indication of a new phase to switch over to from an initial phase or determining that the output power phase should be switched from an initial main current path to a new main current path.

[0045] In block 1103, the processing circuitry 803 controls the first mechanical switch 310 of an initial main current path 310, the second mechanical switch 310 and the one or more power electronic switches 320 of an initial power electronic path 312 connected in parallel with the initial main current path, the first mechanical switch of the new main current path and the second mechanical switch and the one or more power electronic switches of a power electronic path connected in parallel with the new main current path to switch the output power phase from the initial main current path to the new main current path while reducing disturbances on a load of the output power phase during changeover from the initial main current path to the new main current path.

[0046] Figure 12 illustrates an embodiment of switching the output power phase from the initial main current path to the new main current path while reducing disturbances on a load of the output power phase during changeover from the initial main current path to the new main current path while reducing disturbances on a load of the output power phase during changeover from the initial mechanical path to the new mechanical path.

[0047] Turning to Figure 12, in block 1201, the processing circuitry 403 activates the initial power electronics path 318. In block 1203, the processing circuitry 403 deactivates the first mechanical switch 310 of the initial main current path 312.

[0048] In block 1205, the processing circuitry 403 deactivates the initial power electronics path 318. In block 1207, the processing circuitry 403 activates the new power electronics path 318. In some embodiments, the processing circuitry 403 delays the activating of the new power electronics path for a specified time period after deactivating the initial power electronics path.

[0049] In block 1209, the processing circuitry 403 activates the new main current path. In block 1211, the processing circuitry 403 deactivates the new power electronics path. In some embodiments, the processing circuitry 403, responsive to the one output phase being connected to the new phase, transmits an indication of the switchover towards a utility node.

[0050] In activating the initial power electronics path or the new power electronics path, the processing circuitry 403 switches on the second mechanical switch 310 of the initial power electronics path or the new power electronics path followed by turning on the one or more power electronic switches 320 of the initial power electronics path or the new power electronics path and in deactivating the initial power electronics path or the new power electronics path, the processing circuitry 403 turns off the second mechanical switch 310 of the initial power electronics path or the new power electronics path and the one or more power electronic switches 320 of the initial power electronics path or the new power electronics path at a zero crossing of current flowing through the initial power electronics path or the new power electronics path. [0051] Thus, an HPS 300 has a plurality of input power terminals 306 each adapted to be connected to a different power source phase (e.g., phase A, B, or C of a three phase power system). The HPS 300 also has a plurality of mechanical paths (i.e., main current paths) 312 each connected to one of the input terminals 306 and the output power phase 308, each mechanical path 312 having an inductor 308 and a first mechanical switch 310. The HPS 300 also has a plurality of power electronic paths 318, each power electronic path connected in parallel with one of the plurality of mechanical paths and connected to the one of the input terminals 306 and the output power phase 314, each power electronic path comprising one or more power electronic switches 320 and a second mechanical switch 310. The HPS 300 also has a controller 302 communicatively coupled to the controller (302) communicatively coupled to the first mechanical switch (310) of each of the plurality of mechanical paths (312), the one or more power electronic switches (320) and the second mechanical switch (310) of each of the plurality of power electronic paths (318).

[0052] The operations that the controller 302 is configured to perform is described above. For example, the controller 302 is configured to receive a changeover message to switch the output power phase from an initial main current path connected to an initial power source phase to a new main current path connected to a new power source phase or determine that the output power phase should be switched from the initial main current path to the new main current path. The controller 302 is also configured to control the first mechanical switch of the initial main current path, the second mechanical switch and the one or more power electronic switches of an initial power electronic path connected in parallel with the initial main current path, the first mechanical switch of the new main current path and the second mechanical switch and the one or more power electronic switches of a power electronic path connected in parallel with the new main current path to switch the output power phase from the initial main current path to the new main current path while reducing disturbances on a load of the output power phase during changeover from the initial main current path to the new main current path.

[0053] Explanations are provided below for various abbreviations/acronyms used in the present disclosure.

Abbreviation Explanation

HPS Hybrid Phase Selector

DMS distribution management system

SC AD A supervisory control and data acquisition

DA distribution automation

SA substation automation

[0054] Additional explanation is provided below. [0055] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

[0056] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0057] In the above-description of various embodiments of present inventive concepts, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of present inventive concepts. 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 present inventive concepts belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0058] When an element is referred to as being "connected", "coupled",

"responsive", or variants thereof to another element, it can be directly connected, coupled, or responsive to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected", "directly coupled", "directly responsive", or variants thereof to another element, there are no intervening elements present. Like numbers refer to like elements throughout. Furthermore, "coupled", "connected", "responsive", or variants thereof as used herein may include wirelessly coupled, connected, or responsive. 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. Well-known functions or constructions may not be described in detail for brevity and/or clarity. The term "and/or" (abbreviated ‘7”) includes any and all combinations of one or more of the associated listed items.

[0059] It will be understood that although the terms first, second, third, etc. may be used herein to describe various elements/operations, these elements/operations should not be limited by these terms. These terms are only used to distinguish one element/operation from another element/operation. Thus a first element/operation in some embodiments could be termed a second element/operation in other embodiments without departing from the teachings of present inventive concepts. The same reference numerals or the same reference designators denote the same or similar elements throughout the specification.

[0060] As used herein, the terms "comprise", "comprising", "comprises", "include", "including", "includes", "have", "has", "having", or variants thereof are open-ended, and include one or more stated features, integers, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, integers, elements, steps, components, functions or groups thereof. Furthermore, as used herein, the common abbreviation "e.g.", which derives from the Latin phrase "exempli gratia," may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. The common abbreviation "i.e.", which derives from the Latin phrase "id est," may be used to specify a particular item from a more general recitation.

[0061] Example embodiments are described herein with reference to block diagrams and/or flowchart illustrations of computer-implemented methods, apparatus (systems and/or devices) and/or computer program products. It is understood that a block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions that are performed by one or more computer circuits. These computer program instructions may be provided to a processor circuit of a general purpose computer circuit, special purpose computer circuit, and/or other programmable data processing circuit to produce a machine, such that the instructions, which execute via the processor of the computer and/or other programmable data processing apparatus, transform and control transistors, values stored in memory locations, and other hardware components within such circuitry to implement the functions/acts specified in the block diagrams and/or flowchart block or blocks, and thereby create means (functionality) and/or structure for implementing the functions/acts specified in the block diagrams and/or flowchart block(s).

[0062] These computer program instructions may also be stored in a tangible computer-readable medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer- readable medium produce an article of manufacture including instructions which implement the functions/acts specified in the block diagrams and/or flowchart block or blocks. Accordingly, embodiments of present inventive concepts may be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.) that runs on a processor such as a digital signal processor, which may collectively be referred to as "circuitry," "a module" or variants thereof.

[0063] It should also be noted that in some alternate implementations, the functions/acts noted in the blocks may occur out of the order noted in the flowcharts. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Moreover, the functionality of a given block of the flowcharts and/or block diagrams may be separated into multiple blocks and/or the functionality of two or more blocks of the flowcharts and/or block diagrams may be at least partially integrated.

Finally, other blocks may be added/inserted between the blocks that are illustrated, and/or blocks/operations may be omitted without departing from the scope of inventive concepts. Moreover, although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

[0064] Many variations and modifications can be made to the embodiments without substantially departing from the principles of the present inventive concepts. All such variations and modifications are intended to be included herein within the scope of present inventive concepts. Accordingly, the above disclosed subject matter is to be considered illustrative, and not restrictive, and the examples of embodiments are intended to cover all such modifications, enhancements, and other embodiments, which fall within the spirit and scope of present inventive concepts. Thus, to the maximum extent allowed by law, the scope of present inventive concepts are to be determined by the broadest permissible interpretation of the present disclosure including the examples of embodiments and their equivalents, and shall not be restricted or limited by the foregoing detailed description.

Claims

1. An apparatus (300) with multiple input power phases and one output power phase, the apparatus comprising: a plurality of input power terminals (306) each adapted to be connected to a different power source phase; a plurality of main current paths (312) each connected to one of the input power terminals and the output power phase (314), each main current path having an inductor (308) and a first mechanical switch (310); a plurality of power electronic paths (318), each power electronic path connected in parallel with one of the plurality of main current paths and connected to the one of the input power terminals and the output power phase, each power electronic path comprising one or more power electronic switches (320) and a second mechanical switch (310); and a controller (302) communicatively coupled to the first mechanical switch (310) of each of the plurality of main current paths (312), the one or more power electronic switches (320) and the second mechanical switch (310) of each of the plurality of power electronic paths (318), the controller (302) configured to: receive (1001) a phase switchover command to switch the one output power phase from an initial main current path connected to an initial power source phase to a new main current path connected to a new power source phase or determine that the one output power phase should be switched from the initial main current path to the new main current path; and control (1003) the first mechanical switch of the initial main current path, the second mechanical switch and the one or more power electronic switches of an initial power electronic path connected in parallel with the initial main current path, the first mechanical switch of the new main current path and the second mechanical switch and the one or more power electronic switches of a power electronic path connected in parallel with the new main current path to switch the one output power phase from the initial main current path to the new main current path while reducing disturbances on a load of the one output power phase during changeover from the initial main current path to the new main current path.

2. The apparatus of claim 1 wherein at least one of the first mechanical switch and the second mechanical switch comprises a contactor.

3. The apparatus of any of claims 1-2, wherein the one or more power electronic switches comprises thyristors.

4. The apparatus of claim 3 wherein the thyristors in a power electronic path are connected to each other in series.

5. The apparatus of any of claims 1-4, further comprising a plurality of printed circuit boards, each having one or more sets of anti-parallel thyristors, gate driver circuitry to energize the one or more sets of anti-parallel thyristors, and an auxiliary power source.

6. The apparatus of any of Claims 1-5 wherein the controller comprises at least one of a transceiver and a network interface, processing circuitry, and memory.

7. The apparatus of any of Claims 1-6 wherein the one or more power electronic switches are connected in series.

8. The apparatus of Claim 7 wherein the one or more power electronic switches are connected in series to achieve voltage scaling for operation in high voltage phases of high voltage transmission lines.

9. The apparatus of any of Claims 1-8 wherein each of the one or more power electronic switches of a power electronic path are mounted to a printed circuit board, PCB, mounted power electronic switch arrangement (800).

10. The apparatus of Claim 9, wherein the PCB mounted power electronic switch arrangement (800) comprises: a plurality of PCBs (802) connected in series, each PCB having: the one or more power electronic switches (320) of a power electronic path (318), wherein the one or more power electronic switches comprises one or more sets of antiparallel silicon controller rectifiers, SCRs, (804) connected in series with at least two power terminals (806, 808); and gate drive circuitry (810) electronically connected to control inputs of the SCRs and to a control terminal (812).

11. The apparatus of Claim 10, wherein the PCB mounted power electronic switch arrangement further comprises a power relay (310) connected in series to one of the plurality of PCBs connected in series.

12. The apparatus of any of Claims 10-11, wherein the PCB mounted power electronic switch arrangement further comprises: an auxiliary power circuit comprising a PCB current transformer (816)to provide auxiliary power (814) to the PCB (800)

13. The apparatus of any of Claims 10-11, wherein the PCB mounted power electronic switch arrangement further comprises a power transformer (818) wherein a secondary winding of the power transformer forms a current loop through the PCB current transformers (816) of the plurality of PCBs to form a secondary winding path (820) of the power transformer with a primary winding of the power transformer connected to input phases of a power source.

14. The apparatus of Claim 13 wherein the secondary winding forms the current loop with other PCB mounted power electronic switch arrangements.

15. The apparatus of any of Claims 10-14, wherein the control terminal receives control commands to turn the SCRs on.

16. A method by a phase selector apparatus having multiple input power phases and one output power phase, a plurality of main current paths each connected to one of the multiple input power phases and the one output power phase, each main current path having an inductor and a first mechanical switch and a plurality of power electronic paths, each power electronic path connected in parallel with one of the plurality of main current paths and connected to one of the multiple input power phases and the one output power phase, each power electronic path comprising one or more power electronic switches and a second mechanical switch, the method comprising: receiving (1001) a phase switchover command to switch the one output power phase from an initial main current path connected to an initial power source phase to a new main current path connected to a new power source phase or determining that the one output power phase should be switched from the initial main current path to the new main current path; and controlling (1003) the first mechanical switch of the initial main current path, the second mechanical switch and the one or more power electronic switches of an initial power electronic path connected in parallel with the initial main current path, the first mechanical switch of the new main current path and the second mechanical switch and the one or more power electronic switches of a new power electronic path connected in parallel with the new main current path to switch the one output power phase from the initial main current path to the new main current path while reducing disturbances on a load of the one output power phase during changeover from the initial main current path to the new main current path.

17. The method of Claim 16, wherein controlling the first mechanical switch of the initial main current path, the second mechanical switch and the one or more power electronic switches of the initial power electronic path connected in parallel with the initial main current path, the first mechanical switch of the new main current path and the second mechanical switch and the one or more power electronic switches of the power electronic path connected in parallel with the new main current path comprises: activating (1101 the initial power electronics path; deactivating (1103) the first mechanical switch of the initial main current path; deactivating (1105) the initial power electronics path; activating (1107) the new power electronics path; activating (1109) the new main current path; and deactivating (1111) the new power electronics path.

18. The method of Claim 17, wherein activating the initial power electronics path or the new power electronics path comprises switching on the second mechanical switch of the initial power electronics path or the new power electronics path followed by turning on the one or more power electronic switches of the initial power electronics path or the new power electronics path and deactivating the initial power electronics path or the new power electronics path comprises turning off the second mechanical switch of the initial power electronics path or the new power electronics path and the one or more power electronic switches of the initial power electronics path or the new power electronics path at a zero crossing of current flowing through the initial power electronics path or the new power electronics path.

19. The method of any of Claims 17-18, further comprising delaying the activating of the new power electronics path for a specified time period after deactivating the initial power electronics path.

20. The method of any of Claims 16-19, further comprising: responsive to the one output power phase being connected to the new phase, transmitting an indication of the switchover towards a utility node.