Method, apparatus, and computer readable storage medium for electrical islanding detection

An apparatus for electrical islanding detection, comprising:

• a voltage reception unit for receiving a three-phase voltage in an electrical power system;
• a first calculation unit for, for the three-phase voltage, calculating a voltage angle sudden-change of each phase, respectively;
• a first determination unit for determining whether an absolute value of the voltage angle sudden-change of each phase is greater than a first angle sudden-change setting value;
• a second determination unit for determining whether directions of the voltage angle sudden-changes of the three phases are the same if the absolute value of the voltage angle sudden-change of each phase is greater than the first angle sudden-change setting value;
• and
• a third determination unit for determining that the electrical islanding appears if the directions of the voltage angle sudden-changes of the three phase are the same.

A method for electrical islanding detection method, comprising:

• receiving a three-phase voltage in an electrical power system;
• determining that an electrical power system enters into a three-phase voltage abnormal state if the three-phase voltage meets any one of the following conditions comprising:
• a zero sequence voltage is greater than a zero sequence voltage setting value;
• or
• a magnitude of any phase voltage is less than a voltage setting value;
• or
• an absolute value of a voltage angle sudden-change of any phase between adjacent voltage cycles is greater than an angle sudden-change setting value;
• determining that the electrical power system enters into a three-phase voltage normal state if none of the above conditions is met and a real-time measurement value of the rate of change of frequency is less than a setting value of the rate of change of frequency;
• when the electrical power system enters into the three-phase voltage abnormal state, calculating an accumulated voltage angle change of the three-phase voltage based on the real-time frequency measurement value;
• determining whether the accumulated voltage angle change is greater than an accumulated angle change setting value;
• and
• determining that the electrical islanding appears if the accumulated voltage angle change is greater than the accumulated angle change setting value,
• wherein when the electrical power system enters into the three-phase voltage normal state, the calculation of the accumulated voltage angle change is stopped.

An apparatus for electrical islanding detection, comprising:

• a voltage reception unit for receiving a three-phase voltage in an electrical power system;
• a first determination unit for determining that the electrical power system enters into a three-phase voltage abnormal state if the three-phase voltage meets any one of the following conditions comprising:
• a zero sequence voltage is greater than a zero sequence voltage setting value;
• or
• a magnitude of any phase voltage is less than a voltage setting value;
• or
• an absolute value of a voltage angle sudden-change of any phase between adjacent voltage cycles is greater than an angle sudden-change setting value;
• determining that the electrical power system enters into a three-phase voltage normal state if none of the above conditions is met and a real-time measurement value of the rate of change of frequency is less than a setting value of the rate of change of frequency;
• a calculation unit for, when the electrical power system enters into the three-phase voltage abnormal state, calculating an accumulated voltage angle change of the three-phase voltage based on the real-time frequency measurement value;
• a second determination unit for determining whether the accumulated voltage angle change is greater than an accumulated angle change setting value;
• and
• a third determination unit for determining that the electrical islanding appears if the accumulated voltage angle change is greater than the accumulated angle change setting value,
• wherein when the electrical power system enters into the three-phase voltage normal state, the calculation unit stops the calculation of the accumulated voltage angle change.