Patent Document ID: 8315742
Application ID: 12310433
Patent Flag: 1

Claim One:
1. A method of forming/defining and solving a loadflow computation model of a power network to affect control of voltages and power flows in a power system, comprising the steps of: obtaining on-line or simulated data of open/close status of all switches and circuit breakers in the power network, and reading data of operating limits of components of the power network including maximum power carrying capability limits of transmission lines, transformers, and PV-node, a generator-node where Real-Power-P and Voltage-Magnitude-V are given/assigned/specified/set, maximum and minimum reactive power generation capability limits of generators, and transformers tap position limits, obtaining on-line readings of given/assigned/specified/set Real-Power-P and Reactive-Power-Q at PQ-nodes, Real-Power-P and voltage-magnitude-V at PV-nodes, voltage magnitude and angle at a reference/slack node, and transformer turns ratios, wherein said on-line readings are the controlled variables/parameters, performing loadflow computation by forming and solving a loadflow model of the power network to calculate complex voltages or their real and imaginary components or voltage magnitude corrections and voltage angle corrections at the power network nodes providing for the calculation of power flowing through different network components, and reactive power generation at PV-nodes, and turns ratio of tap-changing transformers in dependence the set of said obtained-online readings, or given/scheduled/specified/set values of controlled variables/parameters and physical limits of operation of the power network components, forming and solving the said loadflow model of the power network referred to as Patel Decoupled Loadflow (PDL) model as characterized by equations, 
 [ RP]=[GB][f] (51) 
 [ RQ]=[GB][e] (52) wherein, each component of [RP], [RQ], and [GB] are defined by, RP p = [ ( I 1 ⁢ p ⁢ PSH p + I 2 ⁢ p ⁢ QSH p ) / f p ] - [ I 1 ⁢ p ⁡ ( G pp + g p ) - I 2 ⁢ p ⁡ ( B pp + b p ) ] ⁢ e p 2 / f p - ( e p / f p ) ⁢ ∑ q > p ⁢ ( I 1 ⁢ p ⁢ G pq - I 2 ⁢ p ⁢ B pq ) ⁢ e q + ( e p / f p ) ⁢ ∑ q > p ⁢ ( I 2 ⁢ p ⁢ G pq + I 1 ⁢ p ⁢ B pq ) ⁢ f q - ∑ q > p ⁢ ( I 2 ⁢ p ⁢ G pq + I 1 ⁢ ⁢ p ⁢ B pq ) ⁢ e q ( 53 ) RQ p = [ ( I 1 ⁢ p ⁢ PSH p + I 2 ⁢ p ⁢ QSH p ) / e p ] - [ I 1 ⁢ p ⁡ ( G pp + g p ) - I 2 ⁢ p ⁡ ( B pp + b p ) ] ⁢ f p 2 / e p - ( f p / e p ) ⁢ ∑ q > p ⁢ ( I 1 ⁢ p ⁢ G pq - I 2 ⁢ p ⁢ B pq ) ⁢ f q - ( f p / e p ) ⁢ ∑ q > p ⁢ ( I 2 ⁢ p ⁢ G pq + I 1 ⁢ p ⁢ B pq ) ⁢ e q + ∑ q > p ⁢ ( I 2 ⁢ p ⁢ G pq + I 1 ⁢ ⁢ p ⁢ B pq ) ⁢ f q ( 54 ) GB pq = I 1 ⁢ p ⁢ G pq - I 2 ⁢ p ⁢ B pq ( 55 ) GB pp = [ I 1 ⁢ p ⁡ ( G pp + g p ) - I 2 ⁢ p ⁡ ( B pp + b p ) ] ( 56 ) wherein, for solving each linearized sub-problem by Guass-Seidel method, equations (51) and (52) are written as equations (57) and (58) respectively, f p ( r + 1 ) = [ RP p - ∑ q = 1 p - 1 ⁢ GB pq ⁢ f q ( r + 1 ) - ∑ q = p + 1 n ⁢ GB pq ⁢ f q ( r ) ] / GB pp ( 57 ) e p ( r + 1 ) = [ RQ p - ∑ q = 1 p - 1 ⁢ GB pq ⁢ e q ( r + 1 ) - ∑ q = p + 1 n ⁢ GB pq ⁢ e q ( r ) ] / GB pp ( 58 ) wherein, e p and f p are the real and imaginary parts of the complex voltage V p of node-p, PSH p and QSH p are scheduled/specified/set values, except that QSH p at a PV-node is calculated value using specified voltage magnitude constrained by upper and lower reactive power generation capability limits of a PV-node generator, G pq , G pp , and B pq , B pq , are off-diagonal and diagonal elements of real and imaginary parts of the complex admittance matrix of the network respectively, and g p: b p are real and imaginary components of network admittance shunts, q>p indicates node-q is the node adjacent directly connected to node-p excluding the case of q=p, n is the number of nodes in network, superscript ‘r’ indicates the iteration count, and factors I 1p & I 2p can take any values, both the same or different, to be determined experimentally for the best possible convergence and the values can be from −∞,. .. , −2, −1, 0, 1, 2,. .. , ∞, evaluating loadflow computation for any over loaded components of the power network and for under/over voltage at any of the nodes of the power network, correcting one or more controlled variables/parameters and repeating the performing loadflow computation, evaluating, and correcting steps until evaluating step finds no over loaded components and no under/over voltages in the power network, and affecting a change in power flow through components the power network and voltage magnitudes and angles at the nodes of the power network by actually implementing the finally obtained values of controlled variables/parameters after evaluating step finds a good power system or stated alternatively the power network without any overloaded components and under/over voltages, which finally obtained controlled variables/parameters however are stored for acting upon fast in case a simulated event actually occurs.