Extra-high-voltage DC multi-infeed system commutation failure prevention and control method and system

Abstract

The invention relates to an extra-high-voltage DC multi-infeed system commutation failure prevention and control method and system. After an AC system breaks down, commutation failure prevention and control of an inverter valve group which is close to an AC fault point in electrical distance is greatly triggered in advance, and therefore, commutation failure of an inverter valve group which is faraway from the AC fault point in electrical distance is possibly caused. According to the application, a coordinated control mode is adopted, and commutation failure prevention coordinated control output of the inverter valve group in the area near the fault is adaptively adjusted according to the turn-off angle drop value of the inverter valve group in the area away from the fault, so that commutation failure of the inverter valve group in the area away from the fault is avoided.

Description

technical field

[0001] The present application belongs to the technical field of electric power systems, and in particular relates to direct current transmission, and in particular to a commutation failure prevention and control method and system for an UHV direct current multi-infeed system. Background technique

[0002] In recent years, with the continuous development of new energy power generation technology, UHV DC transmission has become a relatively mature and reliable technology that can economically realize large-capacity and long-distance transmission of electric energy, which is conducive to the realization of large-scale energy bases in my country and clean energy such as photovoltaics and wind power. Efficient use of energy. With the continuous operation of DC projects in our country, the power grid structure with multiple DC connections in the same area has emerged. These DCs with close electrical distances and the fed AC grid together form a multi-infeed DC tra...

Examples

Embodiment 1

[0062] This embodiment provides a commutation failure prevention and control method for an UHV DC multi-infeed system, such as figure 1 shown, including:

[0063] Step 1, when the AC power grid fails, obtain the real-time measurement values ​​of the cut-off angles of all the inverter valve groups of the DC system in the remote area of ​​the fault point;

[0064] Step 2, subtracting the cut-off angle of each inverter valve group during stable operation from the real-time measured value of the cut-off angle to obtain the corresponding cut-off angle difference of each inverter valve group;

[0065] Step 3, take the maximum value of each turn-off angle difference, and select the adaptive commutation failure prevention control coefficient according to the maximum value; the commutation failure prevention control coefficient is the fault severity in the commutation failure prevention controller The proportional coefficient between the trigger amount and the advance trigger.

[00...

Embodiment 2

[0103] Embodiment 2 provides a commutation failure prevention and control system for an UHV DC multi-infeed system, including:

[0104]The cut-off angle difference measurement module is used to obtain the real-time measured values ​​of the cut-off angles of all the inverter valve groups of the DC system in the remote area of ​​the fault point, and compare the cut-off angles of each inverter valve group when they are in stable operation with the described The real-time measured value of cut-off angle is subtracted to obtain the corresponding cut-off angle difference of each inverter valve group;

[0105] The commutation failure prevention control coefficient selection module is used to select the adaptive commutation failure prevention control coefficient according to the maximum value of each turn-off angle difference;

[0106] The voltage enabling module is used to determine whether the voltage drop of the AC power grid on the inverter side of the inverter valve group near th...

technical field

[0001] The present application belongs to the technical field of electric power systems, and in particular relates to direct current transmission, and in particular to a commutation failure prevention and control method and system for an UHV direct current multi-infeed system. Background technique

[0002] In recent years, with the continuous development of new energy power generation technology, UHV DC transmission has become a relatively mature and reliable technology that can economically realize large-capacity and long-distance transmission of electric energy, which is conducive to the realization of large-scale energy bases in my country and clean energy such as photovoltaics and wind power. Efficient use of energy. With the continuous operation of DC projects in our country, the power grid structure with multiple DC connections in the same area has emerged. These DCs with close electrical distances and the fed AC grid together form a multi-infeed DC tra...

Examples

Embodiment 1

[0062] This embodiment provides a commutation failure prevention and control method for an UHV DC multi-infeed system, such as figure 1 shown, including:

[0063] Step 1, when the AC power grid fails, obtain the real-time measurement values ​​of the cut-off angles of all the inverter valve groups of the DC system in the remote area of ​​the fault point;

[0064] Step 2, subtracting the cut-off angle of each inverter valve group during stable operation from the real-time measured value of the cut-off angle to obtain the corresponding cut-off angle difference of each inverter valve group;

[0065] Step 3, take the maximum value of each turn-off angle difference, and select the adaptive commutation failure prevention control coefficient according to the maximum value; the commutation failure prevention control coefficient is the fault severity in the commutation failure prevention controller The proportional coefficient between the trigger amount and the advance trigger.

[00...

Embodiment 2

[0103] Embodiment 2 provides a commutation failure prevention and control system for an UHV DC multi-infeed system, including:

[0104]The cut-off angle difference measurement module is used to obtain the real-time measured values ​​of the cut-off angles of all the inverter valve groups of the DC system in the remote area of ​​the fault point, and compare the cut-off angles of each inverter valve group when they are in stable operation with the described The real-time measured value of cut-off angle is subtracted to obtain the corresponding cut-off angle difference of each inverter valve group;

[0105] The commutation failure prevention control coefficient selection module is used to select the adaptive commutation failure prevention control coefficient according to the maximum value of each turn-off angle difference;

[0106] The voltage enabling module is used to determine whether the voltage drop of the AC power grid on the inverter side of the inverter valve group near th...

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