Insulation Class

This code indicates the maximum operating temperature the motor’s / generator’s winding insulation can withstand without failure based on an average 20,000 hour lifetime.

The maximum temperature is the sum of the ambient (normally 40 deg C), maximum temperature rise ratings of the motor/generator and allowance for “hot spot” winding. For example Temperature Tolerance Class F: 40^oC + 105^oC + 10^oC = 155^oC.

Temperature Tolerance Class	Maximum Operation Temperature Allowed	Allowable Temperature Rise at full load 1.0 service factor motor
	oC	oC
A	105	60
B	130	80
F	155	105
H	180	125

Insulation classes are directly related to motor life. Each 10 deg C rise above the motor’s rating can reduce motor life by one-half. Please refer to below graphic winding temperatures (dec C) versus insulation life (hrs)

References:

http://www.engineeringtoolbox.com/nema-insulation-classes-d_734.html

http://www.engineersedge.com/motors/motors_definitions.htm

http://tristate.apogee.net/mnd/mfnrins.asp

 

IP Rating / Code

This is one of the Codes that I always face in my daily work. I write this for easy reference for everyone who needs it. I list also the references / sources in case you need more information regarding this Code.  

 

IP Rating Code stands for International Protection rating or Ingress Protection rating. It classifies the degrees of environmental protection in electrical enclosures which consist of three digits as follow:

1.       Protection from solid objects or materials

2.       Protection from liquids (water)

3.       Protection against mechanical impacts (commonly omitted)

 

The summary of the degree is below:

	1st Number	2nd Number	3rd Number
0	No protection	No protection	No protection
1	>50 mm, e.g. hand	dripping water	0.225 joule, e.g. 150g weight falling from 15cm height
2	>12.5 mm, eg. finger	dripping water when tilted up to 15°	0.375 joule, e.g. 250g weight falling from 15cm height
3	>2.5 mm, eg. tools	spraying water	0.5 joule, e.g. 250g weight falling from 20cm height
4	>1 mm, eg. wires	splashing water	2.0 joule, e.g. 500g weight falling from 40cm height
5	dust protected	water jets	6.0 joule, e.g. 1.5kg weight falling from 40cm height
6	dust tight	powerful water jets	20.0 joule, e.g. 5kg weight falling from 40cm height
7		immersion up to 1 m
8		immersion beyond 1 m

 

Reference:

http://en.wikipedia.org/wiki/IP_Code

http://www.engineeringtoolbox.com/ip-ingress-protection-d_452.html

http://www.machineryautomation.com.au/automation-technology/ingress-protection.html

 

My First Publication: Flexible Generator Maintenance Scheduling in a Practical System Using Fuzzy Logic and Genetic Algorithm

Together with my supervisor, my project was published as a chapter in this book on Page 395-413: Flexible Generator Maintenance Scheduling in a Practical System Using Fuzzy Logic and Genetic Algorithm

About the book:

Hybrid intelligent systems are becoming a very important problem-solving methodology affecting researchers and practitioners in areas ranging from science and technology to business and commerce. This volume focuses on the hybridization of different soft computing technologies and their interactions with hard computing techniques, other intelligent computing frameworks, and agents. Topics covered include: genetic-neurocomputing, neuro-fuzzy systems, genetic-fuzzy systems, genetic-fuzzy neurocomputing, hybrid optimization techniques, interaction with intelligent agents, fusion of soft computing and hard computing techniques, other intelligent systems and hybrid systems applications. The different contributions were presented at the first international workshop on hybrid intelligent systems (HIS1) in Adelaide, Australia.

 

How to design an Integrated Engine-Generator Control Panel

Note: This post is based on my daily works, I just write the general steps and each steps needs to be explored and explained more detail, I hope I can write it in a simple and easily understood book next time. I am stil learning about this control system. Comments and suggestions are welcome 🙂

Engine-Generator Control Panel (EGCP) briefly means a panel which is designed and manufactured to control the Engine-Generator and their accessories. Integrated EGCP combines both the protection and non-protection functions.

A. General

1st Step: To get the Single Line Diagram from the Generator Manufacturer and the Diagram Wirings from the Engine Manufacturer. These drawings are very useful to provide us information about the rating and specification of the Generator such as power rating (kW), reactive power (kVA), voltage (V), number of phase, number of wire, frequency (Hz) and speed (RPM). The drawings also provide us the basic control of the engine and generator, and the Junction Boxes terminals available.

B. Control Section

2nd Step: To identify the Generator Control parts which are normally ship loose together with the generator. The control parts consist of the followings:
1. Automatic Voltage Regulator (AVR) to
2. Manual Voltage Control (MVC)
3. VAR/Power Factor Controller
4. Under Frequency / Over Voltage (UFOV) module
5. Min/Max Excitation Limiter (EL)
6. Diode Fault Detector (DFD)
7. Field Circuit Breaker (FCB)
8. Field Discharge Module (FDM)
9. Surge Capacitor (SC)
10. Lightning Arrestor (LA)

3rd Step: To identify the Engine Control parts which are normally ship loose together with the engine. The control parts consist of the followings:
1. Governor
2. Engine Speed Switch
3. Interfacing Module to Engine Control Panel (ECP)

4th Step: To design the Synchronizing system, Generator Measuring & Protection System Devices for:
· Reverse power protection 32
· Loss of excitation protection 40
· Over excitation protection 24
· Stator current unbalance protection 46
· Generator step transformer Differential protection 87GT
· Auxiliary overvoltage protection 59X
· Negative phase sequence protection 46
· Overcurrent and Shortcircuit protection 50/51
· Ground fault protection 50N/51N
· Over-/Undervoltage protection 59/27
· Over-/Underfrequency protection 81

C. Data Sections

5th Step: To identify the terminals/Junction Boxes available attached in the Generator. The terminals in the junction Boxes are used as the input parameter for the EGCP, which are normally:
1. Permanent Magnet Generator (PMG) and Exciter Field
PMG uses permanent magnet instead of electromagnet to produce the magnetic field, voltage is induced in the stationary armature when the magnetic field is rotated inside of it. PMG deliver rated AC voltage to the voltage regulator. The power supplied by voltage regulator energizes the exciter field. Therefore PMG acts as pilot exciter.
2. Current Transformer (CT)
a. Cross Current Compensation Transformer (CCCT) / Paralleling Current
Transformer to control the division of reactive kVA in proportion to the rating of
generators operating in parallel (metering)
b. Differential Current Transformer (DCT) to measure the current balance between
two conductors for protection relaying
c. Ground Fault Current Transformer (GFCT) to detect the ground fault current for
protection relaying
3. Space Heater to heat up the panel/junction box especially to reduce the humidity and increase the insulation resistance of the 3-phase terminals
4. Resistor Temperature Detector (RTD) is used for temperature sensor for Phase A,B & C, Drive Bearing and Opposite Drive Bearing.
5. Air Filter Switch for Drive End and Opposite Drive End (NO or NC contact)
6. Oil Level Switch for Drive End and Opposite Drive End (NO or NC contact)
7. Differential Pressure Switch is used only in the air-filtered generator type where air filter is used to remove over 78% of the particles with diameter over 5 microns. The switch actuates when the filter become clogged

6th Step: To identify the terminals in Junction Boxes available attached in the Engine. The terminals in the Junction Boxes are used as the input parameter for the EGCP, which are normally:
1. Emergency Stop
2. Start / Stop control
3. Cranking control
4. Running signal
5. Over speed shut down signal
6. Alarm and Shutdown signals

7th Step: To choose the Programmable Logic Controller (PLC) and the Human Machine Interface (HMI) considering: input parameters from Generator, Engine and auxiliaries, output types: alarm, shutdown, CB trip, and interface communication to Engine Control Panel, Motor Control Centres (MCCs), Remote Control System, and SCADA system.

D. Power Supply Section

8th Step: To design the AC and DC power supply system include the battery charger, rectifier and battery

E. Panel Section

9th Step: To design the size and layout of the Panel considering the internal lighting, space heater, exhaust fan, and position/spaces for the ship loosed control parts, and Panel Protection degree (IP rating)

And the last step is to develop the Electrical Drawings for the Engine-Generator Control Panel which consists: Single Line Diagram: AC and DC system, Layout System and Cable Schedule / Termination.

Now, we are ready to manufacture the Engine-Generator Control Panel.

 

MODERN POWER PLANT MANAGEMENT

 

In response to the increasing demand of the electricity in
developing countries and the inability of the government sponsored
National Power Company to fulfill the demand, the market of
Electricity Supply is open to the Independent Power Producer (IPP).
IPP can supply the electricity directly to end users or indirectly by
selling the power to the National Power Company whereas the power
generated will be connected to the existing transmission and distribution
system.

Due to a strict regulation for the environment, a Modern Power Plant
Management is required to reduce the exhaust gas emission and meet the
criteria set by the government. This means an extra cost for the IPP
for the installation of additional system such as Selective Catalyst
Reduction (SCR), Hydrolysis Process, and Oxidation Process. Generally,
the systems are available and progressively improved by the Generator
Set manufacturer.

Furthermore, the increase in the fuel price and the increase of the
Generator Set (Genset) Cost deter the IPP in entering into the
business of electricity. However, by careful and intensive R&D
approaches in a Modern Power Plant Management, a minimum cost yet
reliable power can be achieved simultaneously which result in meeting
the electricity demand and gaining a high business profit. Therefore,
to provide reliable electricity and environmentally friendly power
system in a competitive cost is the main objective of the Modern Power
Plant Management.

Power Plant Management should start from the planning of a Power
Plant. This planning includes the type of Power Plant which considers
the availability of the resources and the capacity of each unit which
consider the existing load profile as well as future load profile.

The wrong design in choosing the capacity of each unit will cause a
high operating and maintenance cost. The rule of thumbs is the
capacity of each unit should be at the same rating. Moreover, IPP
should consider a spinning reserve and contingency plan during the
maintenance. In general, the rating of spinning reserve unit of the
system will be the highest rating of the engine. The wide variants in
the rating of each engine will cause a difficult arrangement for the
Power Plant Engineer in the scheduling of Units for the operation as
well as the maintenance.

Reliable electricity means the supply of power is uninterrupted and
the fluctuations of voltage and frequency are under the accepted range.
Particularly, in the industrial estates, some factories requires zero
breakdown, even a less than a minute of power dip is not acceptable
as it will interrupt the processing in a manufacture which cause the
process to restart again from the beginning, while, the interrupted
process will be redundant.

 

Artificial Intelligence Approach to Maintenance Scheduling in Large Scale Power Systems

Maintenance scheduling affects power system reliability as well as the economics operation. The reliability of the power system assures that the demand is met even though an outage occurred in the system. Generally, the utility provides the spinning reserve. This will cause the increase in the operating cost, yet the reliability of the system is improved. To minimise the cost of operation as well as the maintenance, a good maintenance scheduling is needed considering the operating hours, which determine the down time of the units, the health of the engine by inspecting the specific fuel consumption and the crew as well as resources availability.

An effective and practical maintenance scheduling increases the system reliability, reduces the operation and maintenance cost, and extends the lifetimes of the generators. Moreover, an easily revisable maintenance scheduling is required for the practical points of views in facing the problem of increasing demand as well as the additional units in the larger-scale of power system.

The combination of genetic algorithm and the fuzzy logic, by minimising the operational and maintenance cost as the objective function, is proposed and presented is this paper.

Taken from My B. Eng Thesis, Introduction