Method for analyzing operation state of substation by combining whole grid model with local grid model

Patent metadata

Field	Value
Publication number	US-9851415-B2
Application number	US-201514609632-A
Country	US
Kind code	B2
Filing date	Jan 30, 2015
Priority date	May 27, 2014
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

The disclosure relates to the crossing field between a power transmission of an ultra-high-voltage and a power system simulation, specifically a method for analyzing an operation state of a substation by combining a whole grid model with a local grid model is provided according to the disclosure. The method includes following steps: performing a load flow calculation for the provincial grid to which a ultra-high-voltage line belongs, wherein initial data of the load flow calculation employs a grid model with E format for national power grid dispatching control center; making an equivalent transform for the model, forming an island independently from the provincial grid to which a ultra-high-voltage line belongs, and making a load flow calculation for the island to acquire data of node voltages and line transmission power.

First claim

The invention claimed is:

1. A method for analyzing an operation state of a substation by combining a whole grid model with a local grid model, comprising:
step 1: performing a first load flow calculation on a provincial grid to which a ultra-high-voltage line belongs, wherein initial data of the first load flow calculation takes a grid model with E format for a national power grid dispatching control center; performing an equivalent transformation on the grid model; forming an island independently from the provincial grid to which the ultra-high-voltage line belongs; and performing a second load flow calculation on the island to acquire data of node voltages and line transmission power;
step 2: analyzing a current carrying capacity and the node voltages based on the acquired data in the step 1 to obtain a flow characteristic of a whole grid system after an ultra-high-voltage compatibilization; and providing initial data for a transient simulation;
step 3: establishing a local simulation model in a transient simulation software based on the provided initial data in the step 2 to analyze a primary equipment of an ultra-high-voltage substation after the ultra-high-voltage compatibilization; and obtaining over-voltage, over-load and breaking capability of a circuit breaker of a transformer of the ultra-high-voltage substation in various conditions through calculation; and
step 4: controlling the ultra-high-voltage line in a steady and secure range according to the over-voltage, over-load and breaking capability of the circuit breaker of the transformer of the ultra-high-voltage substation.

2. The method for analyzing an operation state of a substation by combining a whole grid model with a local grid model according to claim 1 , further comprising:
step 5: for an ultra-high-voltage environment of ultra-high-voltage and heavy load operation over a long term, ultra-high-voltage accident, or change in ultra-high-voltage operation mode, determining whether a relay protection and secondary equipment in the ultra-high voltage substation can be protected as required through calculation.

3. The method for analyzing an operation state of a substation by combining a whole grid model with a local grid model according to claim 1 , wherein in the first load flow calculation in the step 1, the flow characteristic of the whole grid system after the ultra-high-voltage compatibilization is analyzed by analyzing the effect of disconnection of a certain circuit on the current carrying capacity of the whole grid system, and by analyzing the effect of a sudden tripping or switching of a large unit of the grids at both sides of ultra-high-voltage substation on voltage fluctuation of the whole grid system after the ultra-high-voltage compatibilization.

4. The method for analyzing an operation state of a substation by combining a whole grid model with a local grid model according to claim 2 , wherein in the first load flow calculation in the step 1, the flow characteristic of the whole grid system after the ultra-high-voltage compatibilization is analyzed by analyzing the effect of disconnection of a certain circuit on the current carrying capacity of the whole grid system, and by analyzing the effect of a sudden tripping or switching of a large unit of the grids at both sides of the ultra-high-voltage substation on voltage fluctuation of the whole grid system after the ultra-high-voltage compatibilization.

5. The method for analyzing an operation state of a substation by combining a whole grid model with a local grid model according to claim 1 , wherein the process of analyzing the primary equipment of the ultra-high-voltage substation using the local simulation model after the ultra-high-voltage compatibilization comprises:
analyzing over-voltage and over-current of a main transformer of the ultra-high-voltage substation after the ultra-high-voltage compatibilization, or when power-off and power-on operation are in a steady state condition, respectively; and
analyzing over-voltage of the main transformer of the ultra-high-voltage substation after the ultra-high-voltage compatibilization, or when power-off and power-on operation are in a fault state condition, respectively,
wherein the fault condition comprises:
a single-phase ground short circuit fault at high-voltage side and medium-voltage side of the main transformer, a three-phase ground short circuit fault at medium-voltage side of the main transformer, and a single-phase ground short circuit fault on a transmission line connected to the ultra-high-voltage substation.

6. The method for analyzing an operation state of a substation by combining a whole grid model with a local grid model according to claim 2 ,
wherein the process of analyzing the primary equipment of the ultra-high-voltage substation using the local simulation model after the ultra-high-voltage compatibilization comprises:
analyzing over-voltage and over-current of a main transformer of the ultra-high-voltage substation after the ultra-high-voltage compatibilization, or when power-off and power-on operation are in a steady state condition, respectively; and
analyzing over-voltage of the main transformer of the ultra-high-voltage substation after the ultra-high-voltage compatibilization, or when power-off and power-on operation are in a fault state condition, respectively,

wherein the fault condition comprises:
a single-phase ground short circuit fault at high-voltage side and medium-voltage side of the main transformer, a three-phase ground short circuit fault at medium-voltage side of the main transformer, and a single-phase ground short circuit fault on a transmission line connected to the ultra-high-voltage substation.

7. The method for analyzing an operation state of a substation by combining a whole grid model with a local grid model according to claim 1 ,
wherein the process of analyzing the primary equipment of the ultra-high-voltage substation using the local simulation model after the ultra-high-voltage compatibilization comprises:
analyzing a breaking capacity of circuit-breakers at three sides of high-voltage, medium-voltage and low-voltage of a main transformer after the ultra-high-voltage compatibilization, or when power-off and power-on operation are in a fault state condition, respectively,

wherein the fault condition comprises: a single-phase ground short circuit fault and an inter-phase short circuit fault at a high-voltage side, a medium-voltage side and a low-voltage side of the main transformer, and a single-phase ground short circuit fault and an inter-phase short circuit fault on a transmission line connected to the ultra-high-voltage substation.

8. The method for analyzing an operation state of a substation by combining a whole grid model with a local grid model according to claim 2 ,
wherein the process of analyzing the primary equipment of the substation using the local simulation model after the ultra-high-voltage compatibilization comprises:
analyzing a breaking capacity of circuit-breakers at three sides of high-voltage, medium-voltage and low-voltage of a main transformer after the ultra-high-voltage compatibilization, or when power-off and power-on operation are in a fault state condition, respectively,

wherein the fault condition comprises: a single-phase ground short circuit fault and an inter-phase short circuit fault at a high-voltage side, a medium-voltage side and a low-voltage side of the main transformer, and a single-phase ground short circuit fault and an inter-phase short circuit fault on a transmission line connected to the ultra-high-voltage substation.

9. The method for analyzing an operation state of a substation by combining a whole grid model with a local grid model according to c

Assignees

• Univ North China Electric Power
• State Grid Corp Of China (Sgcc)
• State Grid Shanxi Changzhi Power Supply Company

Inventors

• Dong Lei
• Li Ye
• Tian Aizhong
• Shen Xiaoli
• Liu Peng
• Wang Chanqiong

Classifications

• G06F30/367

  Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods · CPC title

• G06F2119/06

  Power analysis or power optimisation · CPC title

• G06F30/20

  Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) · CPC title

• G01R31/62

  Testing of transformers · CPC title

• G01R31/58

  Testing of lines, cables or conductors (testing of electric windings G01R31/72) · CPC title