Phasor Measurement Units Model Research Articles

Low-Complexity P Class to M Class PMU Model for Distribution Systems

The paper presents a new PMU (Phasor Measurement Unit) signal processing model compliant with the IEC/IEEE 60255-118-1 standard. The disturbances are rejected by a cascade digital prefilter made of sections, each with one nominal cycle long rectangular impulse response. The frequency is next estimated by the discrete-time frequency-gain transducer (DTFGT). A single section prefilter with the DTFGT is a 1.5 nominal cycle long P class compliant PMU. M class compliance requires 13 sections prefilter what, along with the DTFGT, gives a 13.4 cycle long PMU. By the elongation of the prefilter cascade, with one cycle increment, the transition from the 1.5 cycle P class to the 13.4 cycle M class PMU is obtained. Each cascade section filter is implemented recursively with only two additions and one multiplication independently of the assumed sampling frequency. The phasor is precisely estimated thanks to the proposed correction of amplitude attenuation and phase shift caused by the prefilter. The main advantages of the proposed PMU model are: full compliance with the standard, low computational complexity, superior rejection of harmonics, and possibility of phasor quality assessment based on different length PMU estimations. The proposed PMU model is primary meant for the distribution systems because of high immunity to disturbances and low computational complexity that makes it suitable for implementation in a low-cost hardware platform or as a software module in a virtual instrumentation and large-scale deployment.

Experimental Validation of High-Performance HIL-Based Real-Time PMU Model for WAMS

This article presents a novel real-time hardware-in-loop-based model for synchronized phasor measurement unit (PMU) which incorporates an adaptive observer to estimate the phasor quantities of the actual hardware-based PMU model. The proposed model is feasible for a wide-area monitoring system (WAMS) in modern power grids. The performance of the proposed model is compared to the conventional algorithms of the performance (P)-class and measurement (M)-class PMU models in terms of total vector error and rate of change of frequency under different scenarios (frequency ramp, unbalance with interharmonics, and out-of-bound offnominal frequency). The main advantages of the proposed model compared to existing models are as follows: (1) combining the advantages of both P and M classes in terms of achieving required standard steady-state performance (IEEE C37.118-2005) while capturing the dynamic system performance, (2) improving the redundancy due to PMU loss, (3) allowing faster implementations and advanced visualization tools, and (4) enhancing WAMS accuracy performance. Despite the advantageous introduced utilizing the proposed model, there is still a tradeoff gap between the investment cost of the installed hardware-based PMUs and system redundancy. Moreover, a laboratory-scale six-bus setup is built and tested to demonstrate the practical validity of the proposed model.

Impact of Causality on Performance of Phasor Measurement Unit Algorithms

Most existing phasor measurement units (PMUs) are noncausal PMUs and they compensate for the group delay in PMU applications by shifting time stamps, which may result in high latency that will impair performance of PMU applications. This paper presents causal PMUs to reduce the group delay caused latency without shifting time stamps, and studies the impact of causality on performance of PMU algorithms. The paper first analyzes how causal and noncausal PMUs compensate for the group delay caused by digital filters and it is found that causal PMUs normally reduce latency by the group delay, whereas noncausal PMU will not. Then, the impact of causality on performance of PMU algorithms is investigated and analyzed by using the Hydro Quebec Research Institute (IREQ) PMU model and the IEEE PMU model. Finally, the simulation results carried out on two test systems highlight the difference between the causal method and the noncausal method under fault conditions in realistic multimachine setups.

A PMU Model for Wide-Area Protection in ATP/EMTP

Phasor measurement units (PMUs) are the key components in modern wide-area monitoring, protection, and control systems. This paper addresses the development of a PMU model in the Alternative Transients Program/Electromagnetic Transients Program. The performance of the proposed PMU model is assessed during normal and abnormal operating conditions using an ideal source test circuit and the New England 10-machine 39-bus test power system.

Redundant Location of PMU for Complete Observability and Wide Area Monitoring of Power System using Real Coded Genetic Algorithm

This paper presents an optimal placement of Phasor Measurement Unit model considering measurement redundancy using real coded genetic algorithm(RCGA) for state estimation. This model ensures complete observability of power system for normal conditions as well as contingencies considering Zero injection measurements. Single PMU outages and single branch outages are the contingencies considered in this paper. The optimum solution is obtained by considering objectives such as minimum number of PMU and maximum redundancy. The New England 39, IEEE 57, IEEE118 and practical networks of Indian Grid such as Western regional Indian Power Grid and Northern regional Indian Power Grid are considered for the optimal placement of PMU and it provides verification of globally optimum solution of the proposed model.