US 11,079,255 B2Granted

Angle determination for a generator

AssigneesROLLS-ROYCE plc, MTU Friedrichshafen GmbH, Mtu Onsite Energy GmbH

InventorsJohannes Demharter, Souvik Dasgupta, Michael Kreissl, Amit K Gupta, Vsk Murthy Balijepalli

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Abstract

A method determines a generator system load and/or rotor angle. The generator system has a generator with a generator terminal outputting electrical power generated by the generator, a transformer and a point of common coupling, PCC, terminal. The transformer is between the generator and PCC terminals. The method includes: determining the generator field current; determining the output voltage, the output current and the power factor and/or angle of the output voltage and output current from the generator terminal, and determining the load angle of the generator system, output voltage from the generator terminal, output current from the generator terminal and the power factor and/or angle; and/or determining the output voltage, the output current and the power factor and/or angle of the output voltage and output current, and determining the rotor angle of the generator system, output voltage, output current from the PCC terminal and the power factor and/or angle.

Claims15

Dependent claims

A method of determining a load angle and/or rotor angle of a generator system comprising a generator that is a cylindrical rotor, the generator having a generator terminal for outputting electrical power generated by the generator, a transformer and a point of common coupling (PCC) terminal, the transformer being arranged between the generator terminal and the PCC terminal, the method comprising:

determining a field current of the generator;
determining an open circuit voltage of the generator in dependence on the field current and open circuit characteristics of the generator;
and
determining the load angle and/or rotor angle of the generator system in dependence on the determined open circuit voltage of the generator;
determining an output voltage from the generator terminal, an output current from the generator terminal and a generator power factor angle and/or a generator power factor of the output voltage and output current from the generator terminal, and determining the load angle of the generator system in dependence on the determined field current, output voltage from the generator terminal, output current from the generator terminal and the generator power factor angle and/or the generator power factor;
and/or
determining an output voltage from the PCC terminal, an output current from the PCC terminal and a PCC power factor angle and/or a PCC power factor of the output voltage and output current from the PCC terminal, and determining the rotor angle of the generator system in dependence on the determined field current, output voltage from the PCC terminal, output current from the PCC terminal and the PCC power factor angle and/or the PCC power factor,
wherein the load angle is determined as:
δ
=
θ
+
cos
-
1
(
V
t
E
⁢
cos
⁢
⁢
θ
+
RI
t
E
)
where:
δ is the rotor angle;
Vt is the rms value of the output voltage from the generator terminal;
It is the rms value of the output current from the generator terminal;
E is the rms value of determined open circuit voltage;
θ is the generator power factor angle;
and
R is the internal resistance of the generator.

34 more elements

determining a field current of the generator;
determining an open circuit voltage of the generator in dependence on the field current and open circuit characteristics of the generator;
and
determining the load angle and/or rotor angle of the generator system in dependence on the determined open circuit voltage of the generator;
determining an output voltage from the generator terminal, an output current from the generator terminal and a generator power factor angle and/or a generator power factor of the output voltage and output current from the generator terminal, and determining the load angle of the generator system in dependence on the determined field current, output voltage from the generator terminal, output current from the generator terminal and the generator power factor angle and/or the generator power factor;
and/or
determining an output voltage from the PCC terminal, an output current from the PCC terminal and a PCC power factor angle and/or a PCC power factor of the output voltage and output current from the PCC terminal, and determining the rotor angle of the generator system in dependence on the determined field current, output voltage from the PCC terminal, output current from the PCC terminal and the PCC power factor angle and/or the PCC power factor,
wherein the rotor angle is determined as:
δ
=
θ
+
cos
-
1
(
V
p
E
⁢
cos
⁢
⁢
θ
+
RI
p
E
)
where:
δ is the rotor angle;
Vp is the rms value of the output voltage from the PCC terminal;
Ip is the rms value of the output current from the PCC terminal;
E is the rms value of determined open circuit voltage;
θ is the PCC power factor angle;
and
R is the internal resistance of the generator.

34 more elements

A method of determining a load angle and/or rotor angle of a generator system comprising a generator that is a salient pole machine, the generator having a generator terminal for outputting electrical power generated by the generator, a transformer and a point of common coupling (PCC) terminal, the transformer being arranged between the generator terminal and the PCC terminal, the method comprising:

determining a field current of the generator;
determining an open circuit voltage of the generator in dependence on the field current and open circuit characteristics of the generator;
and
determining the load angle and/or rotor angle of the generator system in dependence on the determined open circuit voltage of the generator;
determining an output voltage from the generator terminal, an output current from the generator terminal and a generator power factor angle and/or a generator power factor of the output voltage and output current from the generator terminal, and determining the load angle of the generator system in dependence on the determined field current, output voltage from the generator terminal, output current from the generator terminal and the generator power factor angle and/or the generator power factor;
and/or
determining an output voltage from the PCC terminal, an output current from the PCC terminal and a PCC power factor angle and/or a PCC power factor of the output voltage and output current from the PCC terminal, and determining the rotor angle of the generator system in dependence on the determined field current, output voltage from the PCC terminal, output current from the PCC terminal and the PCC power factor angle and/or the PCC power factor,
wherein the rotor angle is determined as:
δ
=
cos
-
1
(
V
p
[
E
-
(
X
d
-
X
q
)
⁢
sin
⁡
(
δ
-
θ
)
⁢
I
p
]
⁢
cos
⁢
⁢
θ
+
RI
p
[
E
-
(
X
d
-
X
q
)
⁢
sin
⁡
(
δ
-
θ
)
⁢
I
p
]
)
+
θ
where:
δ is the rotor angle;
Vp is the rms value of the output voltage from the PCC terminal;
Ip is the rms value of the output current from the PCC terminal;
E is the rms value of determined open circuit voltage;
θ is the PCC power factor angle;
R is the internal resistance of the generator;
Xd is the nominal direct synchronous reactance;
and
Xq is the nominal quadrature axis synchronous reactance.

78 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/401,638Filed 2 May 2019
Priority: GB 180879830 May 2018
Published: US 2019/0368898 A15 Dec 2019
Granted: 3 Aug 2021
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G01D 5/242
Influencing the magnitude of a current or voltage: by carrying output of an electrodynamic device, e.g. a tachodynamo
G01R 31/343
Testing dynamo-electric machines: in operation
H02P 9/009
Arrangements for controlling electric generators for the purpose of obtaining a desired output: circuit arrangements for detecting rotor position
H02P 9/006
Arrangements for controlling electric generators for the purpose of obtaining a desired output: means for protecting the generator by using control