Control of reactive power export and import

1 . A method for a central controller of an electrical power distribution network to control an exporting and importing of reactive power by nodes of the network, the method comprising:

identifying, by the central controller, one node of the network having a capability of exporting Q units of reactive power to the network and N nodes of the network each having a capability of importing reactive power from the network, wherein the N nodes do not comprise the one node, wherein N is at least 2, and wherein initially Q>0 or Q<0;

sorting, by the central controller, the N nodes in an ascending order of relative distance from the one node, wherein the sorted N nodes, denoted as nodes 1, . . . , node N, have a capability of importing Q1, . . . , QN units of reactive power and are at a relative distance of R1, . . . , RN from the one node, respectively;

setting, by the central controller, a node index n to 0;

performing a loop over the sorted N nodes, a next iteration of the loop comprising:

incrementing, by the central controller, n by 1;

computing, by the central controller, Q′ as a function of Q, Qn, and m(Rn), wherein Q′ denotes an amount of reactive power to be exported to the network by the one node, and wherein m(Rn) is a reactive power scale factor that is a function of Rn;

sending, by the central controller, a first electromagnetic signal to the one node, wherein the first electromagnetic signal causes the one node to export the amount Q′ of reactive power to the network;

computing, by the central controller, Q″ as a function of Q′ and Qn, wherein Q″ denotes an amount of reactive power to be imported from the network by node n;

sending, by the central controller, a second electromagnetic signal to node n, wherein the second electromagnetic signal causes node n to import the amount Q″ of reactive power from the network; and

after the one node has exported the amount Q′ of reactive power to the network in response to the first electromagnetic signal, computing, by the central controller, Q=Q−Q′ followed by: if ABS(Q)=0 or n=N then exiting the loop, otherwise branching, by the central controller, to the incrementing n by 1 to perform a next iteration of the loop.

2 . The method of claim 1 , wherein computing Q′ comprises:

computing Pn=Qn*(1+m(Rn)); and

if ABS(Q)−ABS(Pn)>0 then computing Q′=Pn, otherwise computing Q′=Q.

3 . The method of claim 1 , wherein computing Q″ comprises:

if ABS(Q′)−ABS(Qn)>0 then computing Q″=Qn, otherwise computing Q″=Q.

4 . The method of claim 1 , wherein initially Q>0.

5 . The method of claim 1 , wherein initially Q<0.

6 . The method of claim 1 , wherein only one iteration of the loop is performed.

7 . The method of claim 1 , wherein at least two iterations of the loop are performed.

8 . The method of claim 7 , wherein only less than N−1 iterations of the loop are performed.

9 . The method of claim 1 , wherein N−1 iterations of the loop are performed.

10 . The method of claim 1 , further comprising:

if computing Q′ comprises computing Q′=Q then computing, by the central controller, T=ABS(Q′/(1+t(Rn))), otherwise computing, by the central controller, T=Q, wherein t(Rn) is a token scale factor that is a function of Rn; and

providing, by the central controller to node n, T tokens that can be subsequently exchanged with the network for real or reactive power.

11 . A computer program product, comprising one or more computer readable hardware storage devices having computer readable program code stored therein, the program code containing instructions executable by one or more processors of a computer system to implement a method for a central controller of an electrical power distribution network to control an exporting and importing of reactive power by nodes of the network, the method comprising:

identifying, by the central controller, one node of the network having a capability of exporting Q units of reactive power to the network and N nodes of the network each having a capability of importing reactive power from the network, wherein the N nodes do not comprise the one node, wherein N is at least 2, and wherein initially Q>0 or Q<0;

sorting, by the central controller, the N nodes in an ascending order of relative distance from the one node, wherein the sorted N nodes, denoted as nodes 1, . . . , node N, have a capability of importing Q1, . . . , QN units of reactive power and are at a relative distance of R1, . . . , RN from the one node, respectively;

setting, by the central controller, a node index n to 0;

performing a loop over the sorted N nodes, a next iteration of the loop comprising:

incrementing, by the central controller, n by 1;

computing, by the central controller, Q′ as a function of Q, Qn, and m(Rn), wherein Q′ denotes an amount of reactive power to be exported to the network by the one node, and wherein m(Rn) is a reactive power scale factor that is a function of Rn;

sending, by the central controller, a first electromagnetic signal to the one node, wherein the first electromagnetic signal causes the one node to export the amount Q′ of reactive power to the network;

computing, by the central controller, Q″ as a function of Q′ and Qn, wherein Q″ denotes an amount of reactive power to be imported from the network by node n;

sending, by the central controller, a second electromagnetic signal to node n, wherein the second electromagnetic signal causes node n to import the amount Q″ of reactive power from the network; and

after the one node has exported the amount Q′ of reactive power to the network in response to the first electromagnetic signal, computing, by the central controller, Q=Q−Q′ followed by: if ABS(Q)=0 or n=N then exiting the loop, otherwise branching, by the central controller, to the incrementing n by 1 to perform a next iteration of the loop.

12 . The computer program product of claim 11 , wherein computing Q′ comprises:

computing Pn=Qn*(1+m(Rn)); and

if ABS(Q)−ABS(Pn)>0 then computing Q′=Pn, otherwise computing Q′=Q.

13 . The computer program product of claim 11 , wherein computing Q″ comprises:

if ABS(Q′)−ABS(Qn)>0 then computing Q″=Qn, otherwise computing Q″=Q.

14 . The computer program product of claim 11 , wherein initially Q>0.

15 . The computer program product of claim 11 , wherein initially Q<0.

16 . A computer system, comprising one or more processors, one or more memories, and one or more computer readable hardware storage devices, the one or more hardware storage devices containing program code executable by the one or more processors via the one or more memories to implement a method for a central controller of an electrical power distribution network to control an exporting and importing of reactive power by nodes of the network, the method comprising:

identifying, by the central controller, one node of the network having a capability of exporting Q units of reactive power to the network and N nodes of the network each having a capability of importing reactive power from the network, wherein the N nodes do not comprise the one node, wherein N is at least 2, and wherein initially Q>0 or Q<0;

sorting, by the central controller, the N nodes in an ascending order of relative distance from the one node, wherein the sorted N nodes, denoted as nodes 1, . . . , node N, have a capability of importing Q1, . . . , QN units of reactive power and are at a relative distance of R1, . . . , RN from the one node, respectively;

setting, by the central controller, a node index n to 0;

performing a loop over the sorted N nodes, a next iteration of the loop comprising:

incrementing, by the central controller, n by 1;

computing, by the central controller, Q′ as a function of Q, Qn, and m(Rn), wherein Q′ denotes an amount of reactive power to be exported to the network by the one node, and wherein m(Rn) is a reactive power scale factor that is a function of Rn;

sending, by the central controller, a first electromagnetic signal to the one node, wherein the first electromagnetic signal causes the one node to export the amount Q′ of reactive power to the network;

computing, by the central controller, Q″ as a function of Q′ and Qn, wherein Q″ denotes an amount of reactive power to be imported from the network by node n;

sending, by the central controller, a second electromagnetic signal to node n, wherein the second electromagnetic signal causes node n to import the amount Q″ of reactive power from the network; and

after the one node has exported the amount Q′ of reactive power to the network in response to the first electromagnetic signal, computing, by the central controller, Q=Q−Q′ followed by: if ABS(Q)=0 or n=N then exiting the loop, otherwise branching, by the central controller, to the incrementing n by 1 to perform a next iteration of the loop.

17 . The computer system of claim 16 , wherein computing Q′ comprises:

computing Pn=Qn*(1+m(Rn)); and

if ABS(Q)−ABS(Pn)>0 then computing Q′=Pn, otherwise computing Q′=Q.

18 . The computer system of claim 16 , wherein computing Q″ comprises:

if ABS(Q′)−ABS(Qn)>0 then computing Q″=Qn, otherwise computing Q″=Q.

19 . The computer system of claim 16 , wherein initially Q>0.

20 . The computer system of claim 16 , wherein initially Q<0.