Nidec D700 Power Plant Excitation Systems Instruction Manual
- June 13, 2024
- Nidec
Table of Contents
Nidec D700 Power Plant Excitation Systems
Product Information
The Power System Stabilizer for D550 and D700 is a digital voltage regulator designed for electric power generation. It provides fast and stable regulation of power generation systems to ensure consistent output frequency and electrical power.
Safety Measures
Before using the machine, it is important to read the installation and
maintenance manual in its entirety. All operations and interventions should be
performed by a qualified technician. Our technical support service is
available to provide additional information as needed.
The manual includes warning symbols to alert users to potential risks. These
symbols indicate operations that can damage the machine or surrounding
equipment, general danger to personnel, and electrical danger to personnel. It
is crucial to understand and heed these warning symbols.
Any servicing or repair operations on the AVR should be carried out by
personnel trained in the commissioning, servicing, and maintenance of
electrical and mechanical components. When the generator is driven at a
frequency below 28 Hz for more than 30 seconds with an analogue AVR, its AC
power supply must be disconnected.
Product Usage Instructions
To install and maintain the Power System Stabilizer for D550 and D700, follow the instructions provided in the installation and maintenance manual.
PSS Activation and Configuration
The PSS (Power System Stabilizer) activation and configuration can be done
using the EasyReg Advanced system. The manual provides detailed instructions
on how to unlock the PSS function and configure it accordingly.
Table of Contents
The manual includes the following sections
- PSS Description
- PSS2C implementation in D550 and D700
- PSS Activation and configuration in EasyReg Advanced
- Unlock function PSS
- PSS configuration
For more detailed information on the Power System Stabilizer for D550 and D700, refer to the manual provided.
This manual concerns the alternator AVR which you have just purchased. We wish to draw your attention to the contents of this maintenance manual.
SAFETY MEASURES
Before using your machine for the first time, it is important to read the
whole of this installation and maintenance manual.
All necessary operations and interventions on this machine must be performed
by a qualified technician.
Our technical support service will be pleased to provide any additional
information you may require.
The various operations described in this manual are accompanied by
recommendations or symbols to alert the user to potential risks of accidents.
It is vital that you understand and take notice of the following warning
symbols.
WARNING
Warning symbol for an operation capable of damaging or destroying the
machine or surrounding equipment.
Warning symbol for general danger to personnel.
Warning symbol for electrical danger to personnel.
All servicing or repair operations performed on the AVR should be undertaken
by personnel trained in the commissioning, servicing and maintenance of
electrical and mechanical components.
WARNING
This AVR can be incorporated in a EC-marked machine.
This manual is to be given to the end user.
- © 2022 Moteurs Leroy-Somer SAS
- Share Capital : 38,679,664 €, RCS Angoulême 338 567 258.
- We reserve the right to modify the characteristics of this product at any time in order to incorporate the latest technological developments. The information contained in this document may therefore be changed without notice.
- This document may not be reproduced in any form without prior authorization.
- All brands and models have been registered and patents applied for.
Power System Stabilizer for D550 and D700 digital voltage regulator
Introduction
Overall, AVRs, or Automatic Voltage Regulators, allow to obtain more stable
power generation system due to their fast dynamics. However, these very fast
regulations may create, in certain operating conditions, oscillations of the
rotor angle of the machines. This leads to ripple on the output frequency and
electrical power of the machines.
The oscillation frequency range of these perturbations may be divided into
three different groups, linked with the origin of the corresponding
oscillations
- The range 0.1Hz to 1Hz corresponds to the low-frequency inertial mode;
- The range 1Hz to 2Hz corresponds to the local mode or interarea mode;
- And the range 2Hz to 3Hz corresponds to the intra plant mode.
To limit the negative effects of these oscillations, it is possible to use an additional functionality of the AVR called PSS (Power Stabilizer System) which, depending on the active power and the frequency variations, will act on the generator excitation level to limit the undesired oscillations of the system.
PSS Description
Several PSS structures exist and the one named PSS2C has been implemented into
the D550 and the D700 digital AVRs.
As mentioned above, a PSS aims to increase the damping level of the global
power system over a certain frequency range. For that purpose, the idea is to
measure signals that are representative of the power oscillations (generally
frequency, speed or active power) and to optimally combine them to act on the
voltage regulator setpoint. Indeed, a bias added to the voltage setpoint will
tend to change the excitation level of the generator, and therefore to
increase or decrease the magnetic link between stator and rotor. If these
excitation level modifications are optimally determined, then they will
counteract the rotor speed oscillation, thus increasing the stability of the
global system.
According to its topology, a PSS is generally composed of two main parts
arranged in different orders
- The first part deals with the input signals processing. The different inputs of the system are indeed adequately scaled, shifted and arranged to serve the purposes of the PSS.
- The second part is the output stage of the PSS. It consists in phase shifting the output of the PSS in order to apply the right correction on the voltage setpoint. A scaling is applied as well to obtain the expected level of damping.
IEEE PSS structures
The IEEE committee has defined different types of standard PSS structures.
These structures represent different level of complexity and therefore have
different characteristics. Following the application and the needs regarding
the additional damping required by the system, the user can choose one
appropriate structure that will offer sufficient degrees of freedom to achieve
the expected behaviour. The different structures proposed in the IEEE 421.5
2016 are briefly described in the following subsections.
PSS1A
The PSS1A is the simplest structure that can be implemented. The single input
is generally connected to a rotating velocity signal (speed or frequency) or
to the electrical power. This structure is composed of
- A transducer block (T6 time constant) representing the signal measurement dynamic;
- A global gain block of the PSS Ks;
- A washout filter (T5 time constant) for suppressing the signal DC bias;
- A second-order filter accounted for refining the input or output signal shaping;
- Two lead-lag filters (T1 to T4) for adjusting the phase shift of the PSS output signal.
PSS2C
The PSS2C is a widely used structure, providing a very good compromise between
efficient system damping and implementation complexity. Its dual-input is
generally connected to a speed-representing signal (Vsi1) and to the
electrical power of the generator (Vsi2). The PSS then combines these signals
to calculate the integral of accelerating power, that gives a good image of
mechanical power changes in the system. This structure is composed of
- Washout filters (Tw1, Tw2, Tw3 and Tw4) for suppressing the very low frequency components in the input signals;
- A transducer block (T6);
- A low-pass filter (T7) together with two scaling gains (Ks2 and Ks3) for adjusting the electrical power input;
- A Ramp Tracking Filter (T8 and T9) used for preventing the PSS from reacting to slow electrical power changes;
- A global PSS gain Ks1;
- Four lead-lag filters (T1, T2, T3, T4, T10, T11, T12 and T13) for adjusting the phase shift of the output signal.
PSS3C
The PSS3C is a dual-input PSS, generally connected to the electrical power
(Vsi1) and rotor angular speed deviation (Vsi2). The global structure is quite
simple, the inputs are processed and composed to generate an accelerating
power signal. It is composed of
- Two transducer blocks (T1 and T2) with Ks1 and Ks2 gains;
- Three washout blocks (Tw1, Tw2 and Tw3) for the inputs and the accelerating power signal;
- Two second-order filters for output signal phase compensation (A1 to A8).
PSS4C
The PSS4C has been created to seperately deal with the low- medium- and high-
frquency bands related to the power oscillations of the system. The rotor
speed deviation is measured differently for low and intermediate frequencies
on one side and high-frequencies on the other. Each band is composed of
- A differential filter (blocks before the summing points ;
- A gain;
- A limiter.
All the outputs are summed and limited to provide the PSS output signal.
PSS5C
The PSS5C is a kind of simplified PSS4C with a single input. The processing of
this input is then separated and provides two signals for the different
frequency bands. As for the PSS4C, the aim is here to provide a specific
response of the PSS with regards to the band in which the input frequency
lies. 
1.1.6. PSS6C
The structure of the PSS6C is derived from the PSS3C one with a dual input
(typically generator electrical power output and rotor angular speed
deviation) to produce a signal proportional to the accelerating power. A
conversion between PSS3C and PSS6C is possible. 
1.1.7.
PSS7C
Finally, the PSS7C is a hybrid between PSS2C and PSS6C. It has the same
structure as the PSS2C but the phase compensation is provided by a canonical
state equation, as for PSS6C. It is possible to transform PSS2C into PSS7C
parameters.
PSS2C detailed description
The PSS integrated in the D550 and the D700 follows the PSS2C structure. This
section details the different parts of this structure and the associated
parameters.
Input signals
The PSS2C has two input signals
- Vsi1 is the electrical frequency deviation. It is limited between Vsi1max and Vsi1min, typically 2 and -2;
- Vsi2 is the generator electrical active power. It is limited between Vsi2max and Vsi2min, typically 2 and -2.
Input signal processing
The input signals are pre-processed in order to isolate the significant part
for PSS operation. This pre-processing stage consists in different filters
- For Vsi1 input (frequency deviation)
- A transducer filter (unity gain low-pass filter) that takes into account the measurement system time constant T6;
- Two washout filters for deleting the very low frequencies of the signals. These filters consist in unity gain high-pass filters (Tw1 and Tw2).
- For Vsi2 input (electrical active power)
- A low-pass filter with Ks2 gain (T7 time constant) to cut off the high-frequency components compared to the relevant frequency range;
- Two washout filters for deleting the very low frequencies of the signals (Tw3 and Tw4). One of the two washout filters may be bypassed thanks to a logic block.
The gain Ks3 is generally set to 1 and the two input signals are combined to create the integral of the mechanical power. The previous relation is derived from
Ramp Tracking Filter
The integral of the mechanical power is then sent to a Ramp Tracking Filter.
This high-order filter aims to allow low-frequency mechanical power changes to
pass through and prevent the system from reacting when submitted to fast
changes in the electrical power. Indeed, the electrical power produced by the
generator may change very fast, that is not the case for the mechanical power.
Therefore, this filter enables to obtain a good image of the real modification
of the mechanical power from changes in the electrical power. Typical values
for this filter are
- M = 5;
- N = 1;
- T8 = 0.5s;
- T9 = 0.1s.
The filtered signal coming from the Ramp Tracking Filter is then combined with the integral of the electrical power in order to obtain the integral of the accelerating power.
Output stage
Finally, the integral of the accelerating power is scaled by the global PSS
gain Ks1 and is submitted to a phase compensation stage. Indeed, in order to
compensate the phase shift created by all the electrical and mechanical
phenomena between the PSS output and the torque applied on the shaft, four
lead-lag filters are present in the PSS structure. This phase compensation can
be accurately configured thanks to eight parameters (T1, T2, T3, T4, T10, T11,
T12 and T13 time constants).
The output signal is finally limited between VSTmax and VSTmin (typically 0.1 and -0.1) and an output logic bloc enables to activate or disactivate the PSS.
PSS2C implementation in D550 and D700
In the D550 and D700 AVR products, PSS is embedded in application firmware. To integrate this function in the firmware, a discretization of the PSS has been used and the corresponding functional diagram is given below. The Output of PSS is a saturated bias integrated in the list of setpoints.
Figure 1 – PSS setpoint integration
PSS Filters integration part is described hereunder
Figure 2 – Full PSS2C Integration
In Figure 2 – Full PSS Integration is described. Based on the IEEE model, all filters embedded in the product to achieve the PSS2C functionality may be found in the picture. However, other filters (in grey) are added and not defined by the standard model, these filters must be configured to optimize the filter block phase.
PSS Activation and configuration in EasyReg Advanced
To configure PSS function in EasyReg Advanced, an Add-on must be installed to unlock the configuration page.
Unlock function PSS
After this installation, go in Add-on page to see new button
Figure 3 – Add on page
In this menu click on PSS option, the page hereunder will appear
On this page, if the connected AVR does not embed PSS function or no AVR is
connected to your computer, the padlock will appear closed. However, if the
function is already unlocked, the padlock will appear open.
If the option is locked, you can set the password by clicking on the padlock
PSS configuration
After enabling the PSS function, by clicking on the next button, a new page
appears with a first set of filters defined in the IEEE standard.
Figure 6 – PSS input part
In this page, all parameters should be set with values given by Leroy-Somer.
Please contact service.epg@leroy-somer.com for assistance.
By clicking on the next button, a new page of configuration will appear.
This page is used to configure the RTF filter
Figure 7 – PSS RTF Part
Here again, all parameters should be set with values given by Leroy-Somer. By clicking on the next button, a new page of configuration will appear.
This page is used to configure the output filters (Lead-Lag)
Figure 8 – PSS Output part
All parameters should be set with values given by Leroy-Somer.
After full parameter set, the configuration can be uploaded into the AVR.
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Nidec D700 Power Plant Excitation
Systems
[pdf] Instruction Manual
D700 Power Plant Excitation Systems, D700, Power Plant Excitation Systems,
Plant Excitation Systems, Excitation Systems, Systems
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