Low voltage micro-phasor measurement unit (μPMU)

Abstract

Phasor measurement units (PMUs) installed in the power grid are currently positioned mainly on the transmission system or in substations. A PMU creating real-time synchrophasor data from the consumer voltage level, called μPMUs, could provide new insight into modern power systems. These units can be created more cheaply, an order of magnitude less, than current commercial PMUs. For this reason, many more PMUs could be deployed and provide a much higher resolution of the distribution grid. There are many new applications for such a visible grid in post-mortem event analysis and identification, as well as near real-time monitoring. This paper describes the hardware limitations impact on developing an accurate synchrophasor along with considerations for μPMUs placement within the distribution grid.

Comparison of Bounds for Optimal PMU Placement for State Estimation in Distribution Grids

“…As shown in [8], splitting the problem in two steps yields the same first-order approximation as solving the problem in one step. Moreover, the posterior minimumvariance estimator using the linear update (6), is equal to the maximum-likelihood using a weighted least-squares approach [13]. Therefore, we can conclude that for an SE method that assumes Gaussian noises and performs a maximum likelihood estimation, the posterior covariance will be approximately the one in (7), and thus the method developed here for optimal sensor placement can be also extended for other SE techniques satisfying these conditions.…”

“…Some work in the literature is focused on using PMUs to achieve topological observability [4], which can be solved using integer linear Adolfo.Anta@ait.ac.at programming [5]. Although cheap PMUs [6] are becoming available for mass deployment, their operational and network communication costs [7] may still prevent installing the required minimum number of sensors to achieve topological observability based only on PMUs, especially in distribution grids. If topological observability is not possible, neither is numerical observability ensured, which is required to solve the SE [4].…”

Applications of synchrophasor technologies in power systems

“…However, a major breakthrough was developed in 2009 when IEEE started a joint project with IEC to harmonize RT communications defined in C37. 118 in [8,9,13] and [14]. A comprehensive summary of synchrophasor standards is formulated in Table 2.…”

“…A commercial lPMU was developed by [118] in which the main function of the device was to calculate voltage, frequency, and phase at the household voltage level. This unit operates at a consumer level voltage and has the capability to capture only one phase.…”

Efficient Convex optimization for Optimal PMU Placement in Large Distribution Grids

“…Some previous work proposes to achieve topological observability [3] by using integer linear programming [4]. However, although cheap PMUs are becoming available [5], their operational and network communication costs [6] may still prevent installing enough units to guarantee topological observability and thus also numerical observability, which is necessary for SE [3]. Therefore, PMUs need to be combined with Supervisory Control And Data Adquisition (SCADA) measurements to solve the SE problem [7].…”