Explain the Five States of Apparatus - SaskPower 2 Book 2/6... · 3 Explain the Five States of...

STUDENT GUIDE

Explain the Five States of Apparatus

TABLE OF CONTENTS

PREREQUISITES......................................................................... 2STUDENT RESOURCES................................................................ 2FORMS OF ENERGY .................................................................... 3STATES OF APPARATUS ............................................................. 5SUMMARY ................................................................................ 17PRACTICE FEEDBACK ................................................................. 17EVALUATION ............................................................................. 17

APPENDIX ................................................................................. 21

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Notes: PREREQUISITES

• Level 1 Apprenticeship Training• Level 2 Apprenticeship: "Alternating Current" modules• Level 2 Apprenticeship: "Describe the Standard Protection Code and Explain Why it is

Required"

Objectives: Upon completion of this module, you will be able to explain terms used in the electrical industry to describe five states of apparatus that can exist and the forms of energy that relate to those states.

Rationale: To achieve a high level of safety, it is critical to understand the five states of apparatus and the forms of energy as they are concepts and terms you will use throughout your career as an electrical worker.

STUDENT RESOURCES

• SaskPower Standard Protection Code Book

LEARNING OBJECTIVES

LEARNING METHODS

EVALUATION METHODS

Describe the forms of energy that impact the five states of apparatus.

Self Learning Final Test

Explain the five states of apparatus.

Self Learning Final Test

3 Explain the Five States of Apparatus

Notes: Lesson 1: Forms of Energy

Learning Objective: Describe the forms of energy that impact the five states of apparatus.

Learning Method: Self Learning

Evaluation Method: Final Test

INTRODUCTION

Apparatus is defined as "all equipment pertaining to the generation, transmission,distribution and use of electrical energy." Examples include lines, transformers, breakers,pumps, motors, valves, relays, etc.

Energy can exist in the electrical or the mechanical sense.

Some examples of sources of electrical energy in Transmission & Distribution are:

• A 25kV three-phase overhead line• Induction on an isolated line that runs parallel to a line that is alive

Some examples of sources of mechanical energy in Transmission & Distribution are:

• The compressed spring in a 72/138kV circuit switcher motor control cabinet• Gaseous pressure in a 25kV SF6 breaker

Forms of Energy

The two forms of energy that pertain to the five states of apparatus are dynamic energy andcharged energy.

Dynamic Energy

Dynamic energy is the energy available when electrical or mechanical apparatus is connectedto a substantial source of energy.

An example of apparatus containing dynamic energy in the electrical sense would be anyoverhead line or underground cable that is directly connected to its normal tap-off, take-offor source.

Charged Energy

Charged energy has no connection to an energy source. It is induced, stored or residualenergy.

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Notes: Examples of charged energy are:

• Capacitive charge in underground primary cable• Induction on an isolated line that parallels a line that is dynamically alive• A compressed spring


Notes: Lesson 2: States of Apparatus

Learning Objective: Explain the five states of apparatus.

Learning Method: Self Learning

Evaluation Method: Final Test

INTRODUCTION

The five states of apparatus are:

• Dynamically alive• Separated• Isolated• De-energized• Disconnected from the system

Dynamically Alive

Dynamically alive is a state that exists when apparatus is connected to a dynamic energysupply.

In the electrical sense:

Connected by means of a transmission medium (i.e. conductors, risers, buss, etc.) to asubstantial source of electrical energy.

Examples of apparatus containing electrical dynamic energy are as follows:

• 72/25kV power transformer connected to the Grid• Distribution transformer connected to an energized 14.4kV line• A panel connected to an energized 480V underground cable

When a Power Line Technician is working on an apparatus using barehand work methods, thepower line is dynamically alive.

DANGER

All electrical apparatus must be considered alive unless confirmed otherwise.

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Notes:

Figure 1. Working Barehand

In the mechanical sense:

Connected to a source of energy such as a motor, pressurized liquids or gas in a closedsystem.

Examples of mechanical dynamic energy in Transmission & Distribution:

• Motor driver compressing a spring in a breaker or circuit switcher motor control cabinet• Air blast breaker connected to a compressed air system

Separated

Separated means the apparatus is disconnected from all sources of dynamic energy, butcontrols have not been put in place to prevent the change of position of the separating device.For example, a line is separated when an OCR handle has been pulled, but the disconnect orblades above it have not been opened (see figure 2).


Notes:

Figure 2. Line is Separated - OCR Handle is Pulled

Apparatus in the separated state does not provide protection to personnel because there is novisual opening and no control has been put in place to prevent the change in position of theseparating device.

Separated apparatus must be considered as containing charged energy and capable of beingconnected to a dynamic energy supply (no controls have been put in place).

Isolated

Isolated is a state that exists when apparatus is separated and controls have been put in placeto prevent the change in position of the separating device.

The controls are tagged in conjunction with:

DANGER

All separated electrical apparatus must be con-sidered alive. Charged energy must always be considered a potential hazard and cannot be completely eliminated.

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Notes: • disabled (i.e. gravity - an open solid blade disconnect), or• removed (i.e. parking - an underground elbow (single or three-phase transformer), or• locked (i.e. padlocks - locking a GOPT switch), or• blocked (i.e apparatus is physically prevented from being operated).

Apparatus in the isolated state does not provide protection to personnel. An isolatedapparatus must be considered as containing charged energy.

When considering the isolating requirement for apparatus, personnel must consider thehazards in the "mechanical sense" as well as in the "electrical sense".

Isolating Devices

Every effort shall be made to use isolating devices with visible contacts. All phases of suchdevices must be inspected to confirm they are open.

If isolating devices with visible contacts are not available, the isolation of the circuit must beconfirmed by a qualified person with:

• an approved potential test indicator, or• an approved voltmeter, or• the application of a grounding device.

DANGER

All isolated electrical apparatus must be consid-ered alive. Charged energy must always be con-sidered a potential hazard and cannot be competely eliminated from apparatus.


Notes:

Figure 3. Breaker - Rack Out Type

Metal clad circuit breakers are acceptable isolating devices if they are removed and the cellis locked and tagged, or if visual separation is confirmed, the breaker may be locked in thetest or disconnected position and tagged. (see figure 3)

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Notes:

Figure 4. Hotstick Operated Three Blade Bypass Switch

Hotstick operated blades may be used as an isolating device when opened and tagged. Gravityprevents them from closing. (see figure 4)


Notes:

Figure 5. Isolating Device - Grasshopper Type Cutout

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Notes:

Figure 6. Isolating Device - Barrel Cutout

When providing isolation at structures with a grasshopper or barrel type cutout:

• Remove the fuse or barrel, remove and secure the hot line clamp and tag the structure• The riser can be left on only if it is unsafe to remove the hot line clamp

• If the pole is unsafe to climb and an aerial device is unavailable or inaccessible, or• Limits of approach cannot be maintained (long riser)


Notes:

Figure 7. Line and load blades on 3-way bypass switches being used as isolating device. The structure is tagged and the blades are open and disabled by gravity.

Examples of devices that may be used as isolating devices are:

• GOPT switches, cutouts and risers• Solid blade disconnects, underground elbows

All devices used for isolation (or the structure/apparatus they are installed on), must betagged.

De-energized

De-energized in the electrical sense is a state that exists when apparatus is isolated andgrounded.

De-energized does not necessarily mean that the apparatus is in an electrically safe zone.Charged energy hazards (induction, capacitive charge, etc.) must be controlled to provide an

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Notes: electrically safe zone.

Grounded means apparatus is intentionally connected to earth through a conductingconnection to prevent a build up of hazardous voltages.

In the mechanical sense, de-energized is the state that exists when apparatus is isolated andnot spring-loaded, free from gaseous pressure and free from poisonous or suffocating gases.

Working grounds:

• Must be installed as per approved bonding and grounding procedures• Create an electrically safe zone by controlling the charged energy hazards• Are the responsibility of the Permit Holder• Are installed under the direction of the Permit Holder after the permit is issued• Are documented in the Permit Holder's Hazard and Risk Assessment/Job Plan• Are not required to be tagged

System/trip grounds:

• Are installed to provide a guarantee of de-energization for a Work Permit or a Work & Test Permit

• Are installed as part of the permit switching plan before the permit is issued• Are installed under the direction of the Issuing Authority• May or may not provide an electrically safe zone • If they do provide an electrically safe zone by controlling the charged energy hazards,

they can be used as working grounds• Are required to be tagged

DANGER

De-energized apparatus must be considered as containing charged energy unless working grounds are installed to provide an electrically safe zone.

NOTE

System grounds may be used as working grounds if the system grounds provide an electrically safe zone.


Notes: De-energizing Devices

De-energizing devices are meant to bond apparatus to the earth's potential (i.e. groundingswitches, ground rods, portable grounds, grounding breaker).

Disconnected from the System

Disconnected from the system is the state that exists when apparatus is not connected to anysource of dynamic energy. New apparatus that has not yet been commissioned into serviceis considered disconnected from the system. For example, a new installation of overhead orunderground apparatus is disconnected from the system until it is physically connected andmade alive for the first time.

With approval from the appropriate Issuing Authority, in certain situations, existing apparatusthat has been in service can be disconnected from the system.

For switch maintenance on remotely controlled lines, the switch can be disconnected fromthe system by one of the following methods:

1. Removal of slack spans2. Removal of risers3. Removal of buss

Transformers can be considered "disconnected from the system" when:

• the HV, LV and tertiary connections are removed, and• all secondary wiring including station service supply to operate AVR, heaters, fans, CT/PT

connections, control, etc., are disconnected, and• all protection inputs associated with the transformer are disabled.

For salvage of remotely and non-remotely controlled lines, the lines can be considered to bedisconnected from the system when:

• one span is removed from each isolating device, and

NOTE

Series insulating devices (i.e. epoxilators or insu-lators cut in-line) are not an acceptable means of disconnection from the system.

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Notes: • one span is removed from all power line crossings.

NOTE

Standard Protection Code Permits are not re-quired for work on apparatus that is disconnect-ed from the system.


Notes: SUMMARY

To summarize this module, you have learned:

• to describe the forms of energy that impact five states of apparatus, and• to explain the five states of apparatus.

PRACTICE FEEDBACK

Review the lessons, ask any questions, and complete the self-test.

EVALUATION

Your final evaluation will be achieving 100% on the final test.

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Notes: REVIEW QUESTIONS

T / F 1. Two forms of energy are charged and dynamic.

2. An example of apparatus containing dynamic energy is a line connected to:

(a) a compressed spring

(b) an isolated capacitor

(c) a separated line that parallels a line that is alive

(d) an underground primary cable that is connected to it's normal take-off

T / F 3. An example of charged energy is a radial line that is isolated, but charged by induction from a live line paralleling it.

T / F 4. The states of apparatus are dynamically alive, separated, isolated, de-energized and disconnected from the system.

5. The state that exists when apparatus is connected to a dynamic energy supply is:

(a) dynamic energy

(b) dynamically alive

(c) separated

(d) charged

T / F 6. Apparatus in the separated state provides a level of safety to personnel.

7. The state that exists when apparatus is isolated from all sources of dynamic energy and is grounded is:

(a) separated

(b) isolated

(c) de-energized

(d) disconnected from the system

8. A newly constructed overhead line that has not been connected is considered:

(a) separated

(b) isolated

(c) de-energized

(d) disconnected from the system

T / F 9. A Standard Protection Code Permit is required when apparatus is "disconnected from the system".

T / F 10. System/trip grounds may be used as working grounds if they provide an electrically safe zone.


Notes: T / F 11. System/trip grounds are installed as part of the switching plan for a permit providing a guarantee of de-energization.

T / F 12. Working grounds are installed under the direction of the Permit Holder.

T / F 13. Working grounds are installed as per approved grounding and bonding procedures to create an electrically safe zone.

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Notes: REVIEW QUESTION SOLUTIONS

1. T

2. an underground primary cable that is connected to it's normal take-off

3. F

4. T

5. dynamically alive

6. F

7. de-energized

8. disconnected from the system

9. F

10. T

11. T

12. T

13. T


APPENDIX

Figure 2. Line is Separated - OCR Handle is Pulled

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Figure 4. Hotstick Operated Three Blade Bypass Switch


Figure 5. Isolating Device - Grasshopper Type Cutout

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Figure 6. Isolating Device - Barrel Cutout


Figure 7. Line and load blades on 3-way bypass switches being used as isolating device. The structure is tagged and the blades are open and disabled by gravity.

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