Power Quality Monitoring
The grid-connected distributed power supply should have the ability to monitor and record power quality indicators such as harmonics, voltage fluctuations and flicker, voltage deviation, and three-phase unbalance at its grid-connected point or public connection point. For the distributed power supply connected to the 10(6)kV~35kV power grid, the statistical value of the power quality index is saved every 10min and uploaded regularly; the distributed power supply connected to the 220/380 V power grid, the statistical values of the power quality indicators shall be saved every 10 minutes, and the power quality data shall be kept for at least one month.
After the distributed power source is connected to the grid, when the power quality of the public connection point does not meet the requirements, alarm information should be generated, and the distributed power supply connected to the 10(6) kV ~ 35 kV power grid should be connected to the distributed power grid, and its operation and management party should report the alarm information to the management department of the connected power grid; for the distributed power supply connected to the 220/380 V power grid, the operation and management party should record the alarm information for the operation and management department of the connected power grid to check.
When the power quality of the public connection point does not meet the requirements due to the grid-connected distributed power supply, measures to improve the power quality should be taken. When the power quality still cannot meet the requirements after taking improvement measures, the distributed power supply should be disconnected from the grid, and the grid can be reconnected only when the power quality meets the requirements.
Communication and Automation
1. Communication security protection
The distributed power supply connected to the grid through the 380 V voltage level, and the distributed power supply connected to the user side through the 10(6) kV voltage level, can use wireless, optical fiber, carrier wave and other communication methods. When wireless communication is used, information and communication security protection measures should be taken.
Direct access to the public power grid through 10(6) kV voltage level, and distributed power grid-connected through 35 kV voltage level, should use private network communication, have the ability to conduct data communication with the power grid dispatching agency, and be able to collect the electrical operating conditions of the power supply, upload it to the power grid dispatching agency, and at the same time have the ability to accept the control and adjustment instructions of the power grid dispatching agency.
When the distributed power supply connected to the power grid adopts optical fiber private network communication, the transmission rate should not be less than 19 200 b/s, and the bit error rate should be better than 1 × 10-9; when using other methods, the transmission efficiency should not be less than 2 400 b/s, and the bit error rate should be better than 1 × 10-5.
2. Guarantee of automation equipment
Distributed power supply, communication and automation backup power supply connected to 10(6) kV~35 kV power grid shall ensure that its communication and automation equipment can run for at least 2 hours when the external power supply is lost, and the basic information provided to the power grid dispatching agency shall include but not be limited to the following:
(1) Electrical analog quantity: voltage, current, active power, reactive power, power factor, frequency of the grid-connected point;
(2) State quantity: the state of the grid-connected disconnecting equipment at the grid-connected point, the fault information, the state signal of the remote terminal of the distributed power supply and the state of the communication channel and other signals;
(3) Electric energy: power generation, on-grid power, off-grid power;
(4) Power quality data: harmonics, voltage fluctuation and flicker, voltage deviation, three-phase unbalance, etc. at the grid connection point;
(5) Other information: the input capacity of the distributed power grid connection point.
3. Information storage capacity
The distributed power supply connected to the 220/380 V power grid shall have the storage capacity of the following information, and store data for at least 3 months for on-site inspection by the operation and management department of the connected power grid:
(1) Electrical analog quantity: the voltage and current of the grid-connected point;
(2) State quantity: signals such as the state and fault information of the grid-connected disconnecting equipment at the grid-connected point;
(3) Electric energy: power generation, on-grid power, off-grid power;
(4) Other information: the input capacity of the distributed power grid connection point.
The distributed power supply connected to the 10(6) kV~35 kV power grid, and its distributed power communication equipment integrated into the power communication optical fiber transmission network, should be integrated into the power communication network management system for unified management.