关键词：风力发电厂；电力；互联电力系统；风电；相量测量单元（PMU）
摘 要：The U.S. power industry is undertaking several initiatives that will improve the operations of the power grid. One of those is the implementation of wide area measurements using phasor measurement units (PMUs) to dynamically monitor the operations and status of the network and provide advanced situational awareness and stability assessment. Wind power as an energy source is variable in nature. Similar to other large generating plants, outputs from wind power plants (WPPs) impact grid operations; conversely, grid disturbances affect the behavior of WPPs. The rapidly increasing penetration of wind power to the grid has resulted in more scrutiny of every aspect of wind plant operations and the demand that large WPPs should behave similarly to conventional power plants under normal and contingency grid conditions. The low-voltage ride-through (LVRT) requirement for WPPs is one such example. Other proposed requirements include frequency response and simulated plant inertia. To completely describe the system condition (state) of the electric power grid at any instant, it is necessary to know the voltage (V), current (I), and apparent power (S) of every point (node/bus) of the system. All three quantities in the alternating current (AC) power system are complex numbers that can be represented by phasors with both a magnitude and a phase angle. Out of the three phasor quantities, only two (any two) are needed to derive the third based on the equation S=VI*=P+jQ. The advance of computing power and worldwide availability of Global Positioning System (GPS) time signals make it possible for a PMU to measure voltage and current at a precise time and output these quantities in phasor form. GPS time signals can be accurate within 1 microsecond (is) anywhere the signal is available. GPS time signals enable the synchronization of measurements across the very large distances that power system interconnections span. This new technology not only produces very accurate phasor measurements but also enables synchronized measurements in the same instant.