GB 38755-2019Code on security and stability for power system (English PDF)

2.1 power system security and power system security analysis

ability of a power system to withstand disturbances during operation, such as sudden loss of components of the power system, or short-circuit failures

Note 1: It characterized by two characteristics:

a) The power system can withstand the transient process caused by the disturbance and transition to an acceptable operating condition;

b) Under the new operating conditions, various constraints shall be satisfied.

Note 2: Security analysis is divided into steady-state security analysis and dynamic security analysis. Steady-state security analysis assumes that power system directly transfers from the steady state before the disturbance to another steady state after the disturbance, without considering the intermediate transient process, and is used to test whether various constraints are satisfied after the disturbance. Dynamic security analysis studies the ability of a power system to maintain stability during the transition from steady state before disturbance to another steady state after disturbance.

2.1 power system security and power system security analysis

ability of a power system to withstand disturbances during operation, such as sudden loss of components of the power system, or short-circuit failures

Note 1: It characterized by two characteristics:

a) The power system can withstand the transient process caused by the disturbance and transition to an acceptable operating condition;

b) Under the new operating conditions, various constraints shall be satisfied.

Note 2: Security analysis is divided into steady-state security analysis and dynamic security analysis. Steady-state security analysis assumes that power system directly transfers from the steady state before the disturbance to another steady state after the disturbance, without considering the intermediate transient process, and is used to test whether various constraints are satisfied after the disturbance. Dynamic security analysis studies the ability of a power system to maintain stability during the transition from steady state before disturbance to another steady state after disturbance.

2.2 power system stability

ability of a power system to maintain stable operation after disturbance

Note: Power system stability can be divided into three categories: rotor angle stability, voltage stability and frequency stability. See Annex A for specific classification.

2.2 power system stability

ability of a power system to maintain stable operation after disturbance

Note: Power system stability can be divided into three categories: rotor angle stability, voltage stability and frequency stability. See Annex A for specific classification.

2.2.1 rotor angle stability

ability of a synchronous generator in a synchronous interconnected power system to maintain synchronous operation after disturbance

Note: Rotor angle instability is caused by insufficient synchronous torque or damping torque. Insufficient synchronous torque leads to aperiodic instability, while insufficient damping torque leads to oscillatory instability. Rotor angle stability can be divided into steady-state rotor angle stability, transient rotor angle stability and dynamic rotor angle stability.

2.2.1 rotor angle stability

ability of a synchronous generator in a synchronous interconnected power system to maintain synchronous operation after disturbance

Note: Rotor angle instability is caused by insufficient synchronous torque or damping torque. Insufficient synchronous torque leads to aperiodic instability, while insufficient damping torque leads to oscillatory instability. Rotor angle stability can be divided into steady-state rotor angle stability, transient rotor angle stability and dynamic rotor angle stability.

2.2.1.1 steady-state rotor angle stability

ability of a power system to automatically recover to the initial operating state without non-periodic loss synchronization of rotor angle after small disturbance

2.2.1.1 steady-state rotor angle stability

ability of a power system to automatically recover to the initial operating state without non-periodic loss synchronization of rotor angle after small disturbance

2.2.1.2 transient rotor angle stability

ability of each synchronous generator to maintain synchronous operation and transition to the new or return to the original steady-state operation mode after the power system is subjected to a large disturbance

Note: Usually refers to rotor angle stability of the first and second swing without loss synchronization.

2.2.1.2 transient rotor angle stability

ability of each synchronous generator to maintain synchronous operation and transition to the new or return to the original steady-state operation mode after the power system is subjected to a large disturbance

Note: Usually refers to rotor angle stability of the first and second swing without loss synchronization.

2.2.1.3 dynamic rotor angle stability

ability of a power system to maintain long-term rotor angle stability under the action of automatic regulation and control devices after small or large disturbances 2.2.1.3.1

small-disturbance dynamic rotor angle stability

ability of a power system to maintain rotor angle stability without divergence oscillation or continuous oscillation under the action of automatic regulation and control devices after small disturbance 2.2.1.3.2

large-disturbance dynamic rotor angle stability

ability of a power system to maintain long-term rotor angle stability under the action of automatic regulation and control devices after large disturbance

Note: Usually refers to the power system without divergence oscillation or continuous oscillation after large disturbance.

2.2.1.3 dynamic rotor angle stability

ability of a power system to maintain long-term rotor angle stability under the action of automatic regulation and control devices after small or large disturbances 2.2.1.3.1

small-disturbance dynamic rotor angle stability

ability of a power system to maintain rotor angle stability without divergence oscillation or continuous oscillation under the action of automatic regulation and control devices after small disturbance 2.2.1.3.2

large-disturbance dynamic rotor angle stability

ability of a power system to maintain long-term rotor angle stability under the action of automatic regulation and control devices after large disturbance

Note: Usually refers to the power system without divergence oscillation or continuous oscillation after large disturbance.

2.2.2 voltage stability

ability of a power system to maintain or restore the system voltage to the allowable range without voltage collapse after the power system is subjected to small or large disturbance

2.2.2 voltage stability

ability of a power system to maintain or restore the system voltage to the allowable range without voltage collapse after the power system is subjected to small or large disturbance

2.2.2.1 steady-state voltage stability

ability of all busbars of a power system to maintain a stable voltage after small disturbance

2.2.2.1 steady-state voltage stability

ability of all busbars of a power system to maintain a stable voltage after small disturbance

2.2.2.2 transient voltage stability

ability of all busbars of a power system to maintain a stable voltage after large disturbance

2.2.2.2 transient voltage stability

ability of all busbars of a power system to maintain a stable voltage after large disturbance

2.2.3 frequency stability

ability of a power system to maintain or restore the system frequency to the allowable range without frequency oscillation or collapse after the power system is subjected to small or large disturbance

2.2.3 frequency stability

ability of a power system to maintain or restore the system frequency to the allowable range without frequency oscillation or collapse after the power system is subjected to small or large disturbance

2.3 N-1 principle

any component of the power system in the normal operation mode (such as generator, AC line, transformer, DC unipolar line, DC converter, etc., the same below) has no failure or is disconnected due to failure, the power system shall be able to maintain stable operation and normal power supply, other components are not loaded, and the voltage and frequency are within the allowable range Foreword II Introduction III

2.3 N-1 principle

any component of the power system in the normal operation mode (such as generator, AC line, transformer, DC unipolar line, DC converter, etc., the same below) has no failure or is disconnected due to failure, the power system shall be able to maintain stable operation and normal power supply, other components are not loaded, and the voltage and frequency are within the allowable range

Contents of GB 38755-2019 Foreword II Introduction III

3.1 Overall requirements

3.1 Overall requirements

3.2 Grid structure

3.2 Grid structure

3.3 Power supply structure

3.3 Power supply structure

3.4 Reactive power balance and compensation

3.4 Reactive power balance and compensation

3.5 Coordination of grid and power supply

3.5 Coordination of grid and power supply

3.6 Power system collapse preventing

3.6 Power system collapse preventing

3.7 Recovery of power system after complete shutdown

3.7 Recovery of power system after complete shutdown

4.1 Steady-state stability reserve criteria of power system

4.2 Security and stability criteria for the ability of power system to withstand large disturbances

4.1 Steady-state stability reserve criteria of power system

4.2 Security and stability criteria for the ability of power system to withstand large disturbances

5.2 Power system steady-state security analysis

5.2 Power system steady-state security analysis

5.3 Power system steady-state stability calculation and analysis

5.4 Power system transient rotor angle stability calculation and analysis

5.5 Power system dynamic rotor angle stability calculation and analysis

5.3 Power system steady-state stability calculation and analysis

5.4 Power system transient rotor angle stability calculation and analysis

5.5 Power system dynamic rotor angle stability calculation and analysis

5.6 Power system voltage stability calculation and analysis

5.6 Power system voltage stability calculation and analysis

5.7 Power system frequency stability calculation and analysis

5.7 Power system frequency stability calculation and analysis

5.8 Power system short-circuit current calculation and analysis

5.9 Subsynchronous oscillation or supersynchronous oscillation calculation and analysis

5.8 Power system short-circuit current calculation and analysis

5.9 Subsynchronous oscillation or supersynchronous oscillation calculation and analysis