Method and apparatus for determining a corrected monitoring voltage
View Patent ↗A method and apparatus for correcting a locally measured inverter voltage. In one embodiment, the method comprises determining a voltage compensation to compensate for a voltage drop along an AC bus between an inverter and a remotely located point on the AC bus; obtaining a voltage measurement at the inverter; applying the voltage compensation to the voltage measurement to determine a corrected voltage measurement; comparing the corrected voltage measurement to a voltage requirement; and performing a corrective action at the inverter when the corrected voltage measurement does not meet the voltage requirement.
1. A method for correcting a locally measured inverter voltage, comprising:
determining a voltage compensation to compensate for a voltage drop that occurs along an AC bus based on the distance between an inverter and a remotely located point on the AC bus;
obtaining a voltage measurement at the inverter;
applying the voltage compensation to the voltage measurement to determine a corrected voltage measurement;
comparing the corrected voltage measurement to a voltage requirement; and
performing a corrective action at the inverter when the corrected voltage measurement does not meet the voltage requirement.
2. The method of claim 1 , wherein the corrective action is one of (i) deactivating the inverter or (ii) performing AC voltage regulation.
3. The method of claim 1 , wherein the voltage compensation is determined based on an initial power from the inverter, a subsequent power from the inverter, and a correction coefficient.
4. The method of claim 3 , wherein the correction coefficient is equal to a ratio of a voltage measurement obtained at the remotely located point and an initial voltage measurement at the inverter.
5. The method of claim 4 , wherein the initial voltage measurement is used to determine the initial power.
6. The method of claim 1 , wherein the remotely located point is a point of common coupling (PCC) between a commercial AC power grid and a distributed generator (DG) that comprises the inverter.
7. The method of claim 6 , wherein the DG is a photovoltaic (PV) system.
8. An apparatus for correcting a locally measured inverter voltage, comprising:
a voltage monitoring module comprising a central processing unit for:
determining a voltage compensation to compensate for a voltage drop that occurs along an AC bus based on the distance between an inverter and a remotely located point on the AC bus;
obtaining a voltage measurement at the inverter;
applying the voltage compensation to the voltage measurement to determine a corrected voltage measurement;
comparing the corrected voltage measurement to a voltage requirement; and
performing a corrective action at the inverter when the corrected voltage measurement does not meet the voltage requirement.
9. The apparatus of claim 8 , wherein the corrective action is one of (i) deactivating the inverter or (ii) performing AC voltage regulation.
10. The apparatus of claim 8 , wherein the voltage compensation is determined based on an initial power from the inverter, a subsequent power from the inverter, and a correction coefficient.
11. The apparatus of claim 10 , wherein the correction coefficient is equal to a ratio of a voltage measurement obtained at the remotely located point and an initial voltage measurement at the inverter.
12. The apparatus of claim 11 , wherein the initial voltage measurement is used to determine the initial power.
13. The apparatus of claim 8 , wherein the remotely located point is a point of common coupling (PCC) between a commercial AC power grid and a distributed generator (DG) that comprises the inverter.
14. The apparatus of claim 13 , wherein the DG is a photovoltaic (PV) system.
15. A system for correcting a locally measured inverter voltage, comprising:
a plurality of photovoltaic (PV) modules; and
a plurality of inverters coupled to the plurality of PV modules in a one-to-one correspondence, wherein each inverter of the plurality of inverters (i) determines a voltage compensation to compensate for a voltage drop along an AC bus between the inverter and a remotely located point on the AC bus; (ii) obtains a local voltage measurement; (iii) applies the voltage compensation to the local voltage measurement to determine a corrected voltage measurement; (iv) compares the corrected voltage measurement to a voltage requirement; and (v) performs a corrective action when the corrected voltage measurement does not meet the voltage requirement.
16. The system of claim 15 , wherein the corrective action is one of (i) deactivating the inverter or (ii) performing AC voltage regulation.
17. The system of claim 15 , wherein the voltage compensation is determined based on an initial power from the inverter, a subsequent power from the inverter, and a correction coefficient.
18. The system of claim 17 , wherein the correction coefficient is equal to a ratio of a voltage measurement obtained at the remotely located point and an initial voltage measurement at the inverter.
19. The system of claim 18 , wherein the initial voltage measurement is used to determine the initial power.
20. The system of claim 18 , wherein the remotely located point is a point of common coupling (PCC) between a commercial AC power grid and a distributed generator (DG) that comprises the plurality of PV modules and the plurality of inverters.