Pq 1stlevel M4 Curriculum

Power Quality Training Courses

Overvoltages and Transients

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Module 4 Overvoltages and Transients

1 INTRODUCTION The aim of this module is to provide the user a detailed overview of the overvoltages and transients related problems, by supplying a guidance for insulation coordination and design, for the selection of the electric strength of equipments, of surge arresters or portective spark gaps, and for structures protection installations. 1.1 General aims This module’s general aim is to provide the attendants the basic knowledge about overvoltages and transients related issues, and some tools for the choice and design of the protecting measures for devices and structures. The aim is achieved through 8 didactic sections, as follows: − Section 1: Overvoltages and transients ; − Section 2: Insulation coordination, definitions, principles and rules; − Section 3: Standard withstand voltage tests; − Section 4: Protective devices; − Section 5: LV, MV and HV surge arresters; − Section 6: Risk assessment for the choice of protecting measures against the effects of lightning − Section 7: Protection of structures against lightning − Section 8: Maintenance and inspection of LPS 1.2 Target groups This module’s target group includes: designers, experts, installers, others, users, utility, and all those who wish to expand their knowledge in Overvoltages and transients issues. 2 SPECIFIC AIMS AND TOPICS The pathway of learning consists of a 2 days course, subdivided in sections (with different duration), with these contents and related aims.

Contents Aims

Contents

Aims

1st day Introduction to overvoltages and transients, concept of insulation coordination, withstand voltage tests and protective devices. The aim of the first day lessons is to introduce the basic knowledge related to overvoltages and transients (definitions, origin, standards, related problems), and the key concept of insulation coordination and protection. 2nd day Risk assessment for the choice of protecting measures, protection of structures against lightning (design of protective installations (LPS)), maintenance and inspections of LPS. The second day lessons aim is to provide the attendants some practical informations and tools on the risk assessment and the choice of protecting measures. The last section of the course will be dedicated to the key problem of installations inspection and maintenance.

Below there’s a detailed overview of the course contents.

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2.1

Pathway of learning flow chart Tim e p rog re ssio n (h ou rs)

S e ction

K n o w le dg e le ve l

E xisting kn ow led g e re qu ire m e n ts

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1

L esson Lesso n an d discu ssion L esson and pra ctica l train ing

O ve rvo lta ge s an d tran sie nts ba sics

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2 In su la tio n c oo rdin ation a sp ects

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3 W ith sta nd vo lta ge te sts b a sics

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5 P ro tec tiv e de vic es c ha ra cteristics

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6 P ro te ction ch oice too ls

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8 S truc tu res pro tec tio n de sign as pe cts

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En d o f th e co urse

3 COURSE DETAILED PROGRAM General notes: − each day there will be one coffee break (30 mins) which will divide the lesson in two parts no longer than 2,5 hours; − at the beginning of the course the lecturer will explain course aims and at the end he will verify their fulfilment through a knowledge test; − the course will be divided in theoretical and practical sections; − at the end of the lessons, a user satisfaction survey will help the lecturer in monitoring the course quality.

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First day: 30 mins

Participants registration and course introduction

60 mins

Section 1: Overvoltages and transients − Definitions (power frequency voltages, temporary voltages, switching and lightning voltages) Modality: Lesson

60 mins

Section 2: Insulation coordination, definitions, principles and rules − Definitions (insulation coordination, self restoring insulation, non self restoring insulation, classification of voltages and overvoltages, standard voltage shapes, insulation level) − Procedures for insulation coordination (general outline of the procedure, determination of the representative overvoltages, determination of the coordination withstand voltages, determination of the required withstand voltages, selection of the rated insulation levels, list of standard short duration power frequency withstand voltages, list of standard impulse withstand voltages, ranges for highest voltage for equipment, selection of the standard insulation levels) Modality: Lesson

30 mins

Coffe break

30 mins

Section 3: Standard withstand voltage tests − General requirements, standard short duration power frequency withstand voltage tests, standard impulse withstand voltage tests Modality: Lesson

60 mins

Section 4: Protective devices (Basics, non linear resistor-type surge arresters, expulsion-type surge arresters, spark gaps, application of different protective devices) − Types (technologies), reference standards, rated values, protection levels Modality: Lesson and discussion

60 mins

Section 5: LV, MV and HV surge arresters − Protection principles, components, implementations of components, products standards, examples. Modality: Lesson and discussion

Second day 90 mins

Section 6: Risk assessment for the choice of protecting measures against the effects of lightning − Introduction, the risk of damage due to lightning, frequency of lightning, damage probability, frequency of damage, average possible losses, procedures for risk assessment. Modality: Lesson and practical training

60 mins

Section 7: Protection of structures against lightning − Design of the LPS, external lightning protection installation (LPI), air termination systems, down-conductor systems, earth termination systems, camping and joints, material and dimensions. Modality: Lesson and practical training

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30 mins

Coffe break

60 mins

Section 8: Maintenance and inspection of LPS − Scope of inspections, order of inspections, maintenance Modality: Lesson and practical training

60 mins

Final discussion; end of the course; user’s questionnaire; knowledge test; Confirmations of attendance

4 TEACHING METHODS Teaching methods are summarized in three main moments: − knowledge transfer (Lesson) topics exposure by the lecturer with the help of slides and eventually other electronic tools (animations, data sheets, didactic movies…); − deepening/learning verification (Discussion) general discussion stimulated by the lecturer (also during the lesson) to verify knowledge transfer and to eventually deepen particular topics; − practical training (and eventually laboratory activities) group work (~ 6 persons/group) for topics deepening, practical problems solution and case studies overview under the supervision of the lecturer. During all the sections, the lecturer will always attend, with teaching and/or activity coordination duty. 5 DIDACTIC MATERIAL AND TOOLS The didactic tools which will be used by the lecturers will be: − Blackboard − Video-projector − Notebook − Microphone The lecture room will be suitable to allow the use of all the above listed didactic tools and to enable group work for the addendants. Each user will receive, during the registration, a folder containing: − course program; − lecture notes containing all or part of the lecture slides. Some additional electronic tools will be available also in electronic format at: http://www.leonardoenergy.org/drupal/ . The folder will also include a user satisfaction questionnaire and a knowledge test (which will be both filled and submitted at the end of the course).

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6 EXISTING KNOWLEDGE REQUIREMENTS The user’s existing knowledge should include: Topic

Basic

Mathematical analysis Statistic Electrical circuits Power systems Power quality

Level Medium •

High

• • • •

7 ACQUIRED COURSE KNOWLEDGE REQUIREMENTS At the end of this course the user will have learned the basic aspects related to overvoltages and transients (definitions, origin, standards, related problems), and the key concept of insulation coordination and protection along with some practical informations and tools on the risk assessment and the choice of protecting measures.

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