The requirements of a network equivalent to be used in a planning tool (such as the SuperOPF being developed at Cornell) for analyzing policy options, impacts on reliability, costs and emissions for networks as vast as the entire Eastern Interconnection, are very different from those assumed in the development of traditional equivalencing procedures. In this paper, a novel network equivalencing approach using bus aggregation techniques is proposed that shows promise for modeling such large systems in the context of analyzing policy options and emissions. This approach is superior to the existing bus aggregation methods in that a) under the base case, the equivalent-system inter-zonal power flows exactly match those calculated using the full-network-model b) as the operating conditions change, errors in line flows are minimized c) the method is more computationally efficient than other bus aggregation methods proposed heretofore. The proposed method is tested on an illustrative six-bus system and promising results are observed.

10aCERTS10aRM11-0051 aShi, Di1 aTylavsky, Daniel, J. uhttps://certs.lbl.gov/publications/improved-bus-aggregation-technique01848nas a2200289 4500008003900000020002200039245007100061210006800132260003800200300001000238520094200248653001001190653002801200653002401228653002901252653002601281653002801307653001301335100001201348700002401360700001201384700002501396700002001421700002301441700002501464856006901489 2012 d a978-1-4673-2306-200aOptimal generation investment planning: Pt. 1: network equivalents0 aOptimal generation investment planning Pt 1 network equivalents aChampaign, IL, USAbIEEEc09/2012 a1 - 63 aThe requirements of a network equivalent to be used in new planning tools are very different from those used in traditional equivalencing procedures. For example, in the classical Ward equivalent, each generator in the external system is broken up into fractions. For newer long-term investment applications that take into account such things as greenhouse gas (GHG) regulations and generator availability, it is computationally impractical to model fractions of generators located at many buses. To overcome this limitation, a modified- Ward equivalencing scheme is proposed in this paper. The proposed scheme is applied to the entire Eastern Interconnection (EI) to obtain several backbone equivalents and these equivalents are tested for accuracy under a range of operating conditions. In a companion paper, the application of an equivalent developed by this procedure is used to perform optimal generation investment planning.

10aCERTS10aEastern Interconnection10ainvestment planning10aoptimal power flow (OPF)10aPower system modeling10areliability and markets10aRM11-0051 aShi, Di1 aShawhan, Daniel, L.1 aLi, Nan1 aTylavsky, Daniel, J.1 aTaber, John, T.1 aZimmerman, Ray, D.1 aSchulze, William, D. uhttps://certs.lbl.gov/publications/optimal-generation-investment01554nas a2200277 4500008003900000020002200039245008300061210006900144260003800213300001000251520067600261653001000937653002400947653002600971653002600997653002801023653001301051100001201064700001201076700002401088700002501112700002001137700002301157700002501180856007101205 2012 d a978-1-4673-2306-200aOptimal generation investment planning: Pt. 2: Application to the ERCOT system0 aOptimal generation investment planning Pt 2 Application to the E aChampaign, IL, USAbIEEEc09/2012 a1 - 63 aPower system planning and market behavioral analysis using the full model of a large-scale network, such as the entire ERCOT system, are computationally expensive. Reducing the full network into a small equivalent is a practical way to reduce the computational burden. In a companion paper, a modified-Ward equivalencing procedure has been proposed. In this paper, the proposed scheme is applied to the ERCOT system to obtain several backbone equivalents, the accuracy of which are tested under a range of operating conditions. The ERCOT equivalent is used in a system planning tool to perform optimal generation investment studies with promising results observed.

10aCERTS10ainvestment planning10aPower system modeling10apower system planning10areliability and markets10aRM11-0051 aLi, Nan1 aShi, Di1 aShawhan, Daniel, L.1 aTylavsky, Daniel, J.1 aTaber, John, T.1 aZimmerman, Ray, D.1 aSchulze, William, D. uhttps://certs.lbl.gov/publications/optimal-generation-investment-002396nas a2200217 4500008003900000245007000039210006900109260001200178300001600190490000700206520174200213653000901955653003601964653001302000100001202013700002502025700002702050700001602077700001802093856006702111 2011 d00aTransmission line parameter identification using PMU measurements0 aTransmission line parameter identification using PMU measurement c05/2011 a1574 - 15880 v213 aAccurate knowledge of transmission line (TL) impedance parameters helps to improve accuracy in relay settings and power flow modeling. To improve TL parameter estimates, various algorithms have been proposed in the past to identify TL parameters based on measurements from Phasor Measurement Units (PMUs). These methods are based on the positive sequence TL models and can generate accurate positive sequence impedance parameters for a fully transposed TL when measurement noise is absent; however, these methods may generate erroneous parameters when the TLs are not fully transposed or when measurement noise is present. PMU field-measure data are often corrupted with noise and this noise is problematic for all parameter identification algorithms, particularly so when applied to short TLs. This paper analyzes the limitations of the positive sequence TL model when used for parameter estimation of TLs that are untransposed and proposes a novel method using linear estimation theory to identify TL parameters more reliably. This method can be used for the most general case: short/long lines that are fully transposed or untransposed and have balanced/unbalance loads. Besides the positive/negative sequence impedance parameters, the proposed method can also be used to estimate the zero sequence parameters and the mutual impedances between different sequences. This paper also examines the influence of noise in the PMU data on the calculation of TL parameters. Several case studies are conducted based on simulated data from ATP to validate the effectiveness of the new method. Through comparison of the results generated by this novel method and several other methods, the effectiveness of the proposed approach is demonstrated.10aAARD10aphasor measurement units (PMUs)10aRM11-0051 aShi, Di1 aTylavsky, Daniel, J.1 aKoellner, Kristian, M.1 aLogic, Naim1 aChow, Joe, H. uhttps://certs.lbl.gov/publications/transmission-line-parameter