US 2026/0086151 A1 · RAPID PREDICTION METHOD AND SYSTEM FOR COMMUTATION FAILURE IN HVDC BASED ON COMMUTATION FAILURE RISK FACTOR

Abstract

Disclosed are a rapid prediction method and system for a commutation failure in a high voltage direct current transmission system (HVDC) based on a commutation failure risk factor, belonging to the technical field of commutation failure prevention in the high voltage direct current transmission system. The method can rapidly predict whether the commutation failure occurs after a fault occurs in a line-commutated converter-HVDC (LCC-HVDC) system, thereby supporting the subsequent prevention of the commutation failure. During the implementation, the method defines a conventional commutation area and an advanced commutation area, and calculates a commutation failure risk factor by integrating the conventional commutation area and the advanced commutation area, thereby predicting the commutation failure. In the method, the present-instant information and the future-instant information of characteristic quantities are comprehensively considered during a prediction process, thereby improving the commutation failure prediction speed.

A rapid prediction method for a commutation failure in a high voltage direct current transmission system (HVDC) based on a commutation failure risk factor, comprising:

calculating the conventional commutation need area Sneed.t, the conventional maximum available commutation area Spro.t, and the advanced commutation need area Sneed.c, the advanced maximum available commutation area Spro.c based on a present-instant commutation voltage magnitude Ucom.t, a present-instant DC current Id.t, a future-instant commutation voltage magnitude Ucom.c, and a future-instant DC current Id.c, respectively, then integrating the conventional commutation areas and the advanced commutation areas through adaptive weight coefficients C1 to C4, to obtain a commutation failure risk factor F, and further determining whether the commutation failure occurs, thereby achieving rapid prediction for the commutation failure upon the occurrence of a fault in a line-commutated converter-HVDC (LCC-HVDC) system;
comprising the following steps:
step 1:
obtaining, in real-time, the present-instant commutation voltage magnitude Ucom.t, the present-instant DC current Id.t, the future-instant commutation voltage magnitude Ucom.c, the future-instant DC current Id.c, and a firing angle instruction value a during an operation process of the LCC-HVDC system, wherein all values are per-unit values;
step 2:
calculating a required commutation area and an available maximum commutation area based on the present-instant commutation voltage magnitude Ucom.t, the present-instant DC current Id.t, and the firing angle instruction value α, and defining the calculated required commutation area and the calculated available maximum commutation area as a conventional required commutation area and a conventional available maximum commutation area, respectively;
and simultaneously, calculating the required commutation area and the available maximum commutation area based on the predicted future-instant commutation voltage magnitude Ucom.c, the future-instant DC current Id.c, and the firing angle instruction value α, and defining the calculated required commutation area and the calculated available maximum commutation area as an advanced required commutation area and an advanced available maximum commutation area, respectively;
step 3:
calculating weight coefficients of the conventional required commutation area and the advanced required commutation area;
step 4:
calculating weight coefficients of the conventional available maximum commutation area and the advanced available maximum commutation area;
and
step 5:
performing weighted integration on the calculated conventional required commutation area, the calculated conventional available maximum commutation area, the calculated advanced required commutation area, and the calculated advanced available maximum commutation area through the weight coefficients, to obtain the commutation failure risk factor, and then predicting whether the commutation failure occurs;
and during a prediction process, adaptively adjusting the weight coefficients of the commutation areas based on prediction errors of characteristic quantities at a previous instant;
in step 5, based on the conventional commutation need area Sneed.t, the conventional maximum available commutation area Spro.t, the advanced commutation need area Sneed.c, the advanced maximum available commutation area Spro.c, and the weight coefficients C1 to C4 calculated in step 2 to step 4, calculating the commutation failure risk factor F in real time according to Formula (8);
F
=
C
1
⁢
S
n
⁢
e
⁢
e
⁢
d
.
c
+
C
2
⁢
S
n
⁢
eed
.
t
+
C
3
⁢
S
pro
.
c
+
C
4
⁢
S
pro
.
t
(
8
)
wherein if F≥0, a system state satisfies a normal commutation condition, and the commutation failure will not occur;
and if F<0,the system state does not satisfy the normal commutation condition, and the commutation failure will occur.

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Rapid prediction method and system for commutation failure in hvdc based on commutation failure risk factor

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Rapid prediction method and system for commutation failure in hvdc based on commutation failure risk factor

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Abstract

Claims6