Travelling-wave based fault protection of high-voltage transmission lines

• US 9,007,733 B2
• Filed: 11/01/2011
• Issued: 04/14/2015
• Est. Priority Date: 11/01/2011
• Status: Active Grant

• Current Assignee: Hitachi Energy Limited (Hitachi, Ltd.)
• Original Assignee: ABB Technology AG (ABB Limited)
• Inventors: Wang, Jianping, Pan, Jiuping, Nuqui, Reynaldo
• Primary Examiner(s): Jackson, Stephen W
• Application Number:
  US14/355,449
• Publication Number:
  US 20140254053A1
• Time in Patent Office: 1,260 Days
• Field of Search: 361/62
• US Class Current: 361/62
• CPC Class Codes: G01R 31/085 in power transmission or distribution lines, e.g. overhead
• CPC Class Codes: G01R 31/088 Aspects of digital computing
• CPC Class Codes: H02H 7/265 making use of travelling wave theory

Abstract

An improved method of fault detection in a high-voltage direct current (HVDC) power transmission line is provided. The fault detection is based on fault-induced travelling waves. The method comprises estimating an amplitude of fault-induced travelling waves at the fault location, and calculating a fault resistance (R_f) based on the estimated amplitude, an estimated pre-fault voltage at the fault location, and a surge impedance of the transmission line. The estimated fault amplitude and the estimated pre-fault voltage are calculated from voltage measurements performed at both ends of the transmission line. Further, a fault detection device is provided.

Claims

1. A method of fault detection in a high-voltage power transmission line, the method comprising:

estimating a pre-fault voltage V₀ at a fault location of the high-voltage power transmission line by;

measuring a first pre-fault voltage V₀^A at a first end of the transmission line,

measuring a second pre-fault voltage V₀^B at a second end of the transmission line, and

calculating the estimated pre-fault voltage as

2. The method according to claim 1, further comprising:

comparing the calculated fault resistance to a threshold value, and

deciding that a high-impedance fault has occurred if the calculated fault resistance exceeds the threshold value.

3. The method according to claim 2, further comprising:

initiating, in response to deciding that a high-impedance fault has occurred, protective measures.

4. A fault detection device comprising:

first measuring means being arranged for measuring, at a first end of a high-voltage power transmission line, a first pre-fault voltage V₀^A and a first fault-induced voltage change Δ

V^A, and

second measuring means being arranged for measuring, at a second end of the transmission line, a second pre-fault voltage V₀^B and a second fault-induced voltage change Δ

V^B,

estimating means being arranged for estimating a voltage amplitude V_f, at a fault location of the high-voltage power transmission line, of a fault-induced travelling wave by calculating an estimated amplitude of the fault-induced travelling wave as V_f=Δ

V^A+Δ

V^B, the estimating means being further arranged to calculate an estimated pre-fault voltage as

5. The device according to claim 4, further comprising comparing means being arranged for:

comparing the calculated fault resistance to a threshold value, and

deciding that a high-impedance fault has occurred if the calculated fault resistance exceeds the threshold value.

6. The device according to claim 5, wherein the comparing means is further arranged for:

initiating, in response to deciding that a high-impedance fault has occurred, protective measures.