Electric power system voltage monitoring and control with energy packets

Patent metadata

Field	Value
Publication number	US-11467197-B2
Application number	US-202117308138-A
Country	US
Kind code	B2
Filing date	May 5, 2021
Priority date	Mar 6, 2020
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

Electric power system voltage control and voltage stability may be calculated using energy packets. Sets of negative energy packet sets normalized by a set of positive and negative energy packet sets may be used for voltage control by adding or removing capacitive units. Energy packet voltage indicators may be calculated using energy packets, and used to determine voltage stability. Control actions may be taken depending on the determined voltage stability.

First claim

What is claimed is:

1. A device for electric power system voltage control, comprising:
an interface for receiving electric power delivery system signals at a first point and a second point separate from the first point, providing current and voltage measurements from the first point and the second point;
an energy packet calculator in communication with the stimulus interface to:
calculate source energy packets over predetermined time interval lengths passing through the first point;
calculate received energy packets over the predetermined time interval lengths passing through the second point;
calculate a ratio of the source energy packets and received energy packets;

and,
a voltage controller in communication with the energy packet calculator to:
compare the ratio and a derivative of the ratio with a threshold; and,
when the ratio and the derivative of the ratio exceed the threshold, initiate a control action.

2. The device of claim 1 , wherein the second location is selected as an area intended for voltage control.

3. The device of claim 1 , wherein the energy packets are calculated by:
calculating products of the current measurements and the voltage measurements obtained over a time interval of the predetermined time interval length;
calculating a time interval power as a sum of the calculated products of the current and voltage measurements over the time interval; and,
calculating an energy packet value for the time interval as a numerical integration of the product of instantaneous voltage and current measurements over that time interval.

4. The device of claim 3 , wherein the energy packet calculator is configured to calculate the energy packet value as:
ε[ n ]= T s Σ m=M(n-1)+1 Mn +v [ m ] i [ m ]

where:
ε[n] represents the energy packet value for sample n;
T s represents the data sample period;
M represents a factor for downsampling;
v[m] represents a voltage value at sample m; and,
i[m] represents a current value at sample m.

5. The device of claim 1 , wherein the energy packet calculator is configured to calculate the ratio as:

EVI
i

⁡

[
k
]

≡

Δ
⁢

E
s
-

⁡

[
k
]

Δ
⁢

E
L
-

⁡

[
k
]

where:
ΔE s − [k] represents a set of the source energy packets;
ΔE L − [k] represents a set of the received energy packets.

6. The device of claim 1 , wherein the control action comprises one selected from the group consisting of: disconnecting a load; connecting a capacitor bank; disconnecting a capacitor bank; adding a source of generation; removing power generation; controlling an inverter to increase reactive power; controlling an inverter to decrease reactive power; and combinations thereof.

7. A system for electric power system voltage stability, comprising:
stimulus interfaces for receiving electric power delivery system signals at a local point and a remote point, providing current and voltage measurements;
an energy packet calculator in communication with the stimulus interfaces to calculate energy packets over predetermined time interval lengths passing through the local and remote points by:
calculating products of the current measurements and the voltage measurements obtained over a time interval of the predetermined time interval length;
calculating a time interval power as a sum of the calculated products of the current and voltage measurements over the time interval;
calculating source energy packet values for the time interval as a numerical integration of the product of instantaneous voltage and current measurements at the local point over that time interval;
calculating received energy packet values for the time interval as a numerical integration of the product of instantaneous voltage and current measurements at the remote point over that time interval; and,
calculating a ratio of the source energy packets and the received energy packets and,

a voltage stability controller in communication with the energy packet calculator to:
compare the ratio of the source energy packets and a derivative of the ratio of the source energy packets to a threshold; and,
when the ratio and the derivative of the ratio exceed the threshold, initiate a control action.

8. The system of claim 7 , wherein the energy packet calculator is configured to calculate the energy packet values as:
ε[ n ]= T s Σ m=M(n-1)+1 Mn v [ m ][ m ]

where:
ε[n] represents the energy packet value for sample n;
T s represents the data sample period;
M represents a factor for downsampling;
v[m] represents a voltage value at sample m; and,
i[m] represents a current value at sample m.

9. The system of claim 7 , wherein the energy packet calculator is configured to calculate the ratio as:

EVI
i

⁡

[
k
]

≡

Δ
⁢

E
s
-

⁡

[
k
]

Δ
⁢

E
L
-

⁡

[
k
]

where:
ΔE s − [k] represents a set of the source energy packets;
ΔE L − [k] represents a set of the received energy packets.

10. The system of claim 7 , wherein the control action comprises one selected from the group consisting of: disconnecting a load; connecting a capacitor bank; adding a source of generation; removing a source of generation; controlling an inverter to increase reactive power; controlling an inverter to decrease reactive power; and combinations thereof.

11. A method for electric power system voltage control, comprising:
obtaining electric power delivery system signals at a first point and a second point separate from the first point;
calculating current and voltage measurements from the signals;
calculating source ene

Assignees

• Schweitzer Engineering Lab Inc

Inventors

• Schweitzer Iii Edmund O
• Zweigle Gregary C
• Blood Ellery A

Classifications

• G01R21/133

  by using digital technique · CPC title

• G06Q50/06 Primary

  Energy or water supply · CPC title

• G01R21/06 Primary

  by measuring current and voltage (G01R21/08 - G01R21/133 take precedence) · CPC title

• G01R19/2513

  Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging · CPC title