Abstract: A detection system of distributed generation islanding based on power frequency carrier, the detection system comprising: a power frequency carrier signal generating device; a power frequency carrier signal detection device; a signal coupling transformer; a substation bus; a distribution power generator (DG); and a safety isolation breaker, wherein the power frequency carrier signal generating device comprises a voltage and current monitor circuit, the power frequency carrier signal generating device is connected with the signal coupling transformer through four three phase four line power cables, and the signal coupling transformer is connected with substation bus through 3 power cables.

Abstract: This present inversion relates to a detection system and detection method of distributed generation islanding based on power frequency carrier. The system includes a power frequency carrier signal generating device near the terminal power distribution substation, a power frequency carrier signal detection device in distributed power grid; the power frequency carrier signal generating device is connected to the substation bus through a signal coupling transformer; the power frequency carrier signal generating device is connected with signal coupling transformer though phase A, B C live wires and the N middle wire, that results in the signal can be send by anyone signal phase, any two phases parallel way or three phases parallel way. The power frequency carrier signal detection device is connected with the low voltage power network though phase A, B and C live wires and the N middle wire.

Abstract: The present invention relates to compounds shown in the general formula (I) or (III), the salts thereof or their mixtures, as well as their preparation method and application. In the general formula (I), X1 is H or CO2H; X2 is OH or phenyl group with 0-2 sulfonic acid substituents, and the sulfonic acid substituents are located at random positions of a benzene ring; when X2 is OH, X1 is H; when X2 is phenyl group with 0-2 sulfonic acid substituents, X1 is H or CO2H; n is an integer of 0-2; and in the general formula (III), n and m are respectively an integer of 0-2. The compounds and the mixtures not only have improved light resistance, ozone resistance and water resistance, but also have excellent water solubility and long-term stability in ink-jet ink.