Field Instruction Switching Activities. Purpose. Scope. Objective. Safety

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1 8.22 Switching Activities Purpose This instruction provides a safe system for switching on Horizon Powers Low Voltage, High Voltage and or Transmission electrical apparatus/network, where switching operations are taking place. Scope This instruction provides the minimum safety requirements for access to Low Voltage, High Voltage and or Transmission Electrical Apparatus in switchyards, switch rooms, cables and overhead lines that applies to all Horizon Power workers, including trainee-switching operators, who switch on Horizon Power s electrical apparatus/network. Objective To ensure all Horizon Power workers that operate Horizon Power s electrical network are appropriately trained for the work they intend to do, and are competent and authorised, by Horizon Power. The main objective of this instruction is to: Minimise the risk of harm to employees, contractors and the public Maintain the integrity of assets owned and operated by Horizon Power Ensure security of Horizon Power s network and continuity of electricity supply to our customers Safety Before commencement of work, a risk assessment must be carried out using the Risk Analysis Procedure (OSH ), to identify and document the hazards and risks associated with the task and ensure appropriate control measures are implemented. It is important that, appropriate control measures must be identified, documented and implemented to lessen or control the identified hazards. Using the correct PPE (see Field Instruction 2.6 Worksite Clothing / Personal Protective Equipment Requirements) Appointing a safety observer (see Field Instruction 2.27 Safety Observer Role) Appointing a trainee-switching operator If arc Flash is listed as a hazard ensuring that only the switching operator that is operating the switchgear is within the arc flash envelope Other personnel in the vicinity Note: If any members of the public are close enough to be at risk, or place the switching operator at risk, during the performance of switching operations, personnel must ask them to move away to a safe distance. If other services attend a substation (e.g. Department of Fire and Emergency Services DFES), the switching operator must advice the Service s team leader of the energised /de-energised status of all primary and secondary plant limits of access. CS10 # FI 8.22 Switching Activities Page 1 of 7

2 DANGER Personnel must be aware that in-service breakers and switchgear could operate at any time. Operation could be due to: Protection operation (trip and possible auto-reclose) Automatic voltage management (capacitor circuit breakers) Load shedding. Instruction Before commencing work on or near Low Voltage, High Voltage and or Transmission apparatus one of the following Permits shall be issued: Electrical Access Permit (EAP) No Horizon Power employee or contractor (who is not authorised to carry out HV live work) shall work on high voltage apparatus which is live or is capable of being made live unless an Electrical Access Permit (EAP) has been issued. Before issuing an EAP, the apparatus, HV / LV equipment must be confirmed de-energised, isolated and earthed. Access is permitted to electrical apparatus only after that apparatus has been isolated, proved de-energised, and earthed (for HV work) or short-circuited (for LV work). The EAP is a written document that stipulates the scope of work and the NPTWTM conditions under which that work is to be carried out. It describes to Recipients: The job area and the scope of work The isolation points The earthing points (i.e. program / permit earths and additional working earths Any additional safety precautions Vicinity Access Permit (VA) Allows personnel to work safely near electrical apparatus that is live or could be made live The Sanction to Test (STT) Permit allows access to specific electrical apparatus by personnel who are required to test new or maintained electrical apparatus, carry out adjustments to electrical apparatus, or fit, test, and remove test devices Switching Communication It is essential that effective communication takes place between all personnel. Adherence to the communication protocol is essential to maintain safety and prevent incidents. The communication protocol involves four key steps: 1. clear ensure that what you say is easy to understand and is not confusing CS10 # FI 8.22 Switching Activities Page 2 of 7

3 2. concise minimise banter and use proper and specific terms 3. confirm information must be repeated by the receiver for confirmation, and 4. complete all of the necessary information is communicated and closed out Written documents must be clear and legible. They must be completed in accordance with Horizon Power s official terminology and instructions. Verbal communication should include: 1. greeting complete with name and location of each party 2. confirm scope of work both parties are working on the same task 3. context establish the current status of the task/job 4. communicate clearly communicate and confirm the next set of tasks, and 5. close out ensure the job is formally complete and all parties clearly acknowledge this status The order of priority for switching is: Emergency takes precedence over non-emergency work. Programed switching takes precedence over all non-programed work. If the risk assessment notes the presence of personnel in the vicinity of the planned switching activities, the switching operator and the onsite Recipient in Charge (RIC) or the Tester in Charge (TIC) must agree on the control measures to be taken, such control measures may include: Requesting that non-switching personnel vacate the area. Not distracting the switching operator during the performance of switching duties. Confirming that applicable protection systems are in service. Personnel who find themselves in an area where switching operations are to take place must: Adhere to requests by the switching operator. Vacate the immediate area. Alert the switching operator to any abnormalities that may affect switching operations. Alert the switching operator if any at risk actions or situations are observed. Points of isolation and the position of programed earths may only be confirmed to the RIC/TIC when the permits being issued. Horizon Power Control Centre (HPCC) has primary control of the electricity systems. Switching Switching operations are actions that involve operating low and high voltage apparatus with the intent to: CS10 # FI 8.22 Switching Activities Page 3 of 7

4 1. Allow access to parts of an electrical apparatus with the intent to connect/remove conductors, fittings, equipment, generators and power lines. 2. De-energise a part of an electrical network. 3. Isolate a part of an electrical network. 4. Re-arrange the electricity supply to an electrical network by means of opening and/or closing switches to change the flow of electricity through the network. All persons that undertake switching operations on Horizon Power networks must be trained, competent and authorised by Horizon Power. Switching Operators will be assessed to verify their competency at two yearly intervals. High Voltage Transition from a live high voltage state to an earthed state for EAP process For the network to transition from a live (hazardous) state, to a de-energised (off) state, there must be a gap (air or other rated insulation) created. This is typically achieved by opening a switch. To progress to an isolated network state, a visible break or other approved isolating switch must be opened, barriered and locked when locking facilities are available or by other means of rendering the network incapable of being inadvertently energised must be put into place and a Danger Do Not Operate tag attached. An earthed state is then achieved following testing procedures and applying program earths. Planned Switching The Switching Operator must contact HPCC before carrying out switching on the network and must be in be possession of an approved switching program. The Switching Operator and the Controller will verify the switching program to confirm: 1. The correct program for the planned work at the right time. 2. The correct item number on the program. 3. The correct location. 4. The correct apparatus. 5. The apparatus is in the expected state prior to operation and is fit to be operated. Following the STOP THINK CHECK protocol is mandatory. After operating the electrical apparatus, the Switching Operator and/or Controller must: 1. Confirm any visible contacts are in the final desired position on each phase. 2. Use mechanical or other positive indications to visually confirm circuit breakers are off before operating the associated dis-connectors (isolators) or racking withdrawable switchgear. 3. Record the exact time a switching operation is executed for each step of the switching program. CS10 # FI 8.22 Switching Activities Page 4 of 7

5 4. Where available, voltage and current indicators must be used by the Controller and/or Switching Operator to confirm switching and the apparatus operational status. Unplanned Switching A Switching Operator may be requested by HPCC to conduct switching actions as the result of an emergency and/or faulty section of the network. The Controller and the Switching Operator will discuss the switching requirements and necessary steps to be undertaken. The Controller will prepare a switching program and dispatch it to the Switching Operator. Power Systems Earthing The purpose of earthing is to: 1. Limit the rise in potential difference in the work area and trigger the protection equipment to disconnect supply if supply is inadvertently restored. 2. Control induction when used in conjunction with equipotential bonding techniques. 3. Safely discharge electrical charges caused by lightning, wind, changes in ambient conditions or altitude. Before electrical apparatus is earthed it must first be tested to prove de-energisation with an approved instrument. The de-energised test is performed using the following sequence: 1. The instrument is proved to be working. 2. The instrument is used to prove the circuit under test is de-energised. 3. The instrument is proved to be working. Earths must be applied immediately after the tests have proven de-energisation. This process must be repeated at all earthing points. Insulated and un-insulated mobile plant is to be appropriately earthed when working on or near any overhead HV and LV wires/conductors (energised or de-energised). Shown in Figure 1 below is the process required to obtain an earthed state for electrical apparatus. CS10 # FI 8.22 Switching Activities Page 5 of 7

6 Hazardous state Live Apply gap (air or other) De-energised Render incapable of energisation and Apply tag Isolated Test and Apply program earth(s) Earthed EAP can now be safely issued Figure 1 - The process required to obtain an earthed state of electrical apparatus. Hand Over Certificate Handover Certificates are used where an electrical site, facility, power line, generator and/or substation is to be handed over from one Operating Authority to another such as, a new zone substation to the HPCC. Handover certificates are also used in conjunction with an Authority for Placing Major Plant / Equipment into Service form (HP System Operations procedure). All persons working at a particular site to be handed over are to sign off the Handover certificate. Low Voltage Safe working techniques must be implemented for work on or near LV electrical apparatus. All LV electrical apparatus must be treated as live unless it is isolated and short-circuited by an approved means. Persons required to work on or near LV network assets must be appropriately trained and authorised. The description and location of the electrical apparatus to be worked on, and the safety measures to be taken, must be clearly understood by all authorised persons intending to work on the electrical apparatus. Isolated and Shorted Low Voltage Dead overhead/underground LV apparatus may be worked on without insulating covers/sleeves or pole top rescue kits. An Electrical Access Permit (EAP) must be issued to all personnel who perform work on any isolated section of Horizon Power s low voltage (LV) network. All isolation points and location of short-circuiting equipment, barriers, locking devices and danger labels must be recorded on the EAP. All members of the crew must sign onto the EAP once they are satisfied that the required safety precautions have been taken. CS10 # FI 8.22 Switching Activities Page 6 of 7

7 Low Voltage Switching All switching operations must be performed by an appropriately authorised Switching Operator using a switching program that has been created by one Switching Operator and checked by another Switching Operator. The operation of the low voltage network is not coordinated or controlled by HPCC and therefore is the responsibility of the local Switching Operator. An LV switching program is required when a work permit is to be issued and, when back-feeding an LV network. Where LV switching is required for operating an LV dis-connector as part of a HV switching program, an LV switching program is not required provided the step is included in the HV program. All LV switching programs must be kept for audit purposes. References Occupational Safety & Heath Act 1984 Occupational Safety & Health Regulations 1996 SHMS OSH Job Risk Analysis (JRA) Procedure SHMS OSH Personal Protective Equipment Electrical Safety Standards Switching Process and Rules Switchgear Instruction Manual Network Permit to Work Training Manual Field Instruction 2.6 Worksite Clothing / Personal Protective Equipment Requirements Field Instruction 2.23 Job Hazard and Risk Management (JRA) Field Instruction 8.6 Switching Authorisations Field Instruction 8.21 Work Permits Field Instruction 8.22 Switching Activities Field Instruction 8.24 Network Tags When planning to visit a Horizon Power substation, personnel must refer too: Field Instruction 2.24 Substation Entry and Distribution Security Key Requirements Field Instructions 4.1 Substation Entry Requirements CS10 # FI 8.22 Switching Activities Page 7 of 7

Field Instruction. Induced voltages can occur in overhead lines, underground cables, or in switchyards.

Field Instruction. Induced voltages can occur in overhead lines, underground cables, or in switchyards. 8.3 Induced Voltage Purpose The purpose of this instruction is to provide awareness of Electrostatic and Electromagnetic induced voltages and the method required to reduce or eliminate it. An induced voltage