Systems and methods for swing angle estimation in an electrical power system

Patent metadata

Field	Value
Publication number	US-10436823-B2
Application number	US-201414519526-A
Country	US
Kind code	B2
Filing date	Oct 21, 2014
Priority date	Aug 16, 2013
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

A method includes obtaining a voltage phasor, a current phasor and a mechanical rotor angle of a source end generator. A receiving end generator impedance and a line impedance between the source end generator and a receiving end generator is also estimated. Furthermore, a swing angle between an internal voltage of the source end generator and an internal voltage of the receiving end generator as a function of obtained voltage phasor, current phasor, mechanical rotor angle and the impedances is estimated. A power swing condition is then determined based on the estimated swing angle.

First claim

The invention claimed is:

1. A method, comprising:
obtaining a voltage phasor (V S ) of a source-end generator;
obtaining a current phasor (I S ) of the source-end generator;
obtaining a mechanical rotor angle (δs) of the source end generator;
estimating a receiving end generator impedance (Z R ) and a line impedance (Z L ) between the source-end generator and the receiving-end generator;
estimating a swing angle (θ) between an internal voltage E S of the source-end generator and an internal voltage E R of the receiving-end generator as a function of the obtained V S , the obtained I S , the obtained δs and the estimated Z L and Z R ;
detecting a power swing condition based on the estimated θ; and
tripping a circuit breaker to isolate the source-end generator from the rest of the system when the power swing condition is detected.

2. The method of claim 1 , wherein estimating the swing angle (θ) comprises determining a real power value (P) and a reactive power value (Q) based on the obtained V S and the obtained I S and the estimated Z L and Z R .

3. The method of claim 2 further comprising estimated a rate of change of swing angle ({dot over (θ)}).

4. The method of claim 3 , wherein estimating the rate of change of swing angle comprises estimating the rate of change of swing angle ({dot over (θ)}) as a function of the mechanical rotor angle (δs), the determined P and the determined Q.

5. The method of claim 4 , wherein the detecting the power swing condition comprises detecting the power swing condition based on the estimated θ and {dot over (θ)}.

6. A system comprising:
a power swing detection device, comprising:
a voltage determination module configured to obtain a voltage phasor (V S ) of a source-end generator;
a current determination module configured to obtain a current phasor (I S ) of the source-end generator;
a rotor angle determination module configured to obtain a mechanical rotor angle (δs) of the source end generator;
an impedance estimation module configured to estimate a receiving end generator impedance (Z R ) and a line impedance (Z L ) between the source-end generator and the receiving-end generator;
a swing angle estimation module configured to estimate a swing angle (θ) between an internal voltage E S of the source-end generator and an internal voltage E R of the receiving-end generator as a function of the obtained V S , the obtained I S , the obtained δs and the estimated Z L and Z R ;
a detection module configured to detect a power swing condition based on the estimated θ; and

a circuit breaker to isolate the source-end generator from the rest of the system when the power swing condition is detected.

7. The power swing detection device of claim 6 , further comprising:
a real power determination module configured to determine a real power value (P) based on the obtained V S and the obtained I S and the estimated Z L and Z R .

8. The power swing detection device of claim 7 , further comprising:
a reactive power determination module configured to determine a reactive power value (Q) based on the obtained V S and the obtained I S and the estimated Z L and Z R .

9. The power swing detection device of claim 8 , wherein the swing angle estimation module is configured to estimate a rate of change of swing angle ({dot over (θ)}) as a function of the determined P and the determined Q.

10. The power swing detection device of claim 9 , wherein the detection module is configured to detect the power swing condition based on the estimated θ and estimated {dot over (θ)}.

11. An electrical power system, comprising:
a receiving-end generator;
a source-end generator configured to be electrically coupled to the receiving-end generator;
a power swing detection device, comprising:
a voltage determination module configured to obtain a voltage phasor (V S ) of the source-end generator;
a current determination module configured to obtain a current phasor (I S ) of the source-end generator;
a rotor angle determination module configured to obtain a mechanical rotor angle (δs) of the source end generator;
an impedance estimation module configured to estimate a receiving end generator impedance (Z R ) and a line impedance (Z L ) between the source-end generator and the receiving-end generator;
a swing angle estimation module configured to estimate a swing angle (θ) between an internal voltage E S of the source-end generator and an internal voltage E R of the receiving-end generator as a function of the obtained V S , the obtained I S , the obtained δs and the estimated Z L and Z R ; and
a detection module configured to detect a power swing condition based on the estimated θ; and

a circuit breaker to isolate the source-end generator from the rest of the system when the power swing condition is detected.

12. The electrical power system of claim 11 , further comprising:
a real power determination module configured to determine a real power value (P) based on the obtained V S and the obtained I S and the estimated Z L and Z R .

13. The electrical power system of claim 12 , further comprising:
a reactive power determination module configured to determine a reactive power value (Q) based on the obtained V S and the obtained I S and the estimated Z L and Z R .

14. The electrical power system of claim 13 , wherein the swing angle estimation module is configured to estimate a rate of change of swing angle ({dot over (θ)}) as a function of the determined P and the determined Q.

15. The electrical power system of claim 14 , wherein the detection module is configured to detect the power swing condition based on the estimated θ and estimated {dot over (θ)}.

Assignees

• Gen Electric

Inventors

• Pan Yan
• Premerlani William James

Classifications

• H02J3/00144 Primary

  using phasor measuring units [PMU] · CPC title

• G01R25/00

  Arrangements for measuring phase angle between a voltage and a current or between voltages or currents · CPC title

• G01R21/133 Primary

  by using digital technique · CPC title

• H02J3/24

  Electricity · mapped topic

• Y04S10/22

  Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units · CPC title