Khattak Electric

13/01/2025

Differential relay slope test with doble testing set
https://youtu.be/mBiDlsMOrX4

11/01/2025

Differential relay slope test with doble testing set

https://youtu.be/mBiDlsMOrX4

17/12/2024

Types of Overcurrent Relays:

1. Instantaneous Overcurrent Relay (IOC)
- Operates instantly when the current exceeds the set value.
- Does not have a time delay.
- Used for phase faults and ground faults.

2. Definite Time Overcurrent Relay (DTOC)
- Operates after a fixed time delay when the current exceeds the set value.
- Time delay is adjustable.
- Used for phase faults and ground faults.

3. Inverse Time Overcurrent Relay (ITOC)
- Operates after a time delay that decreases as the current increases.
- Used for phase faults and ground faults.

4. Very Inverse Time Overcurrent Relay (VITOC)
- Operates after a very short time delay for high fault currents.
- Used for phase faults and ground faults.

5. Extremely Inverse Time Overcurrent Relay (EITOC)
- Operates after an extremely short time delay for very high fault currents.
- Used for phase faults and ground faults.

6. Directional Overcurrent Relay (DOCR)
- Operates based on the direction of the fault current.
- Used for phase faults and ground faults in meshed networks.

7. Ground Fault Overcurrent Relay (GFOCR)
- Operates when a ground fault occurs in the system.
- Used for ground faults in solidly grounded, resistance grounded, or ungrounded systems.

8. Neutral Overcurrent Relay (NOCR)
- Operates when an overcurrent condition occurs in the neutral conductor.
- Used for neutral conductor overcurrent protection.

These types of overcurrent relays are used in power systems to provide protection against overcurrent conditions, which can cause damage to equipment and pose a risk to personnel.

15/12/2024

Troubleshooting Electrical Control Circuits in Substations:

Preparation
1. *Review documentation*: Study the substation's electrical control circuit diagrams, manuals, and maintenance records.
2. *Gather tools*: Collect necessary tools, such as multimeters, circuit testers, and a laptop with relevant software.
3. *Ensure safety*: Wear personal protective equipment (PPE) and follow safety protocols when working with electrical systems.

Step 1: Identify the Problem
1. *Symptom identification*: Determine the specific issue, such as a faulty relay, incorrect wiring, or a malfunctioning circuit breaker.
2. *Gather information*: Collect data on the problem, including the time of occurrence, frequency, and any error messages.

Step 2: Isolate the Problem Area
1. *Circuit analysis*: Analyze the electrical control circuit diagrams to identify the specific area or component causing the issue.
2. *Visual inspection*: Visually inspect the circuit components, wiring, and connections for signs of damage, wear, or corrosion.

Step 3: Test and Measure
1. *Multimeter measurements*: Use a multimeter to measure voltage, current, and resistance in the circuit.
2. *Circuit testing*: Perform circuit tests, such as continuity tests, to identify faulty components or wiring.

Step 4: Analyze and Interpret Results
1. *Data analysis*: Analyze the measurement data to determine the root cause of the problem.
2. *Compare with documentation*: Compare the measurement results with the substation's documentation and manufacturer's specifications.

Step 5: Repair or Replace
1. *Component replacement*: Replace faulty components, such as relays or circuit breakers, with new or refurbished units.
2. *Wiring repairs*: Repair or replace damaged or faulty wiring.
3. *Circuit adjustments*: Adjust circuit settings or parameters to ensure proper operation.

Step 6: Verify and Test
1. *Functional testing*: Perform functional tests to verify the electrical control circuit is operating correctly.
2. *Measureme

12/12/2024

VIDAR TEST

10/12/2024

Differences between Over-Flux Relay and Over-Voltage Relay:

*Over-Flux Relay*

1. *Measures magnetic flux*: Measures the magnetic flux in the transformer core.
2. *Protects against saturation*: Protects the transformer against magnetic saturation, which can cause overheating and damage.
3. *Operates on flux density*: Operates based on the flux density in the transformer core.
4. *Typically used in transformers*: Typically used in power transformers to protect against over-fluxing.

*Over-Voltage Relay*

1. *Measures voltage*: Measures the voltage applied to the transformer or electrical equipment.
2. *Protects against over-voltage*: Protects the transformer or electrical equipment against over-voltage conditions, which can cause insulation breakdown and damage.
3. *Operates on voltage magnitude*: Operates based on the magnitude of the voltage applied to the transformer or electrical equipment.
4. *Typically used in transmission and distribution systems*: Typically used in transmission and distribution systems to protect against over-voltage conditions.

Key differences:

1. *Measurement parameter*: Over-flux relay measures magnetic flux, while over-voltage relay measures voltage.
2. *Protection objective*: Over-flux relay protects against magnetic saturation, while over-voltage relay protects against over-voltage conditions.
3. *Operating principle*: Over-flux relay operates based on flux density, while over-voltage relay operates based on voltage magnitude.
4. *Application*: Over-flux relay is typically used in transformers, while over-voltage relay is typically used in transmission and distribution systems.

08/12/2024

Sweep Frequency Response (SFR) Test of Transformers:

*Objective*

The objective of the SFR test is to measure the transfer function of the transformer over a wide frequency range, typically from 10 Hz to 10 MHz.

*Purpose*

The SFR test is used to:

1. *Verify the transformer's frequency response*: Ensure the transformer's frequency response meets the manufacturer's specifications.
2. *Detect winding or core defects*: Identify any defects or abnormalities in the windings or core that may affect the transformer's performance.
3. *Determine the transformer's resonant frequencies*: Identify the resonant frequencies of the transformer, which can help predict potential problems.

*Test Methodology*

1. *Setup*: Connect the SFR test equipment to the transformer's primary and secondary windings.
2. *Sweep frequency range*: Apply a sweep frequency signal to the primary winding and measure the response on the secondary winding.
3. *Measure transfer function*: Measure the transfer function of the transformer over the sweep frequency range.

*Acceptance Criteria*

1. *Transfer function*: The measured transfer function should match the manufacturer's specifications.
2. *Resonant frequencies*: The resonant frequencies should be within the acceptable range specified by the manufacturer.
3. *No unusual responses*: There should be no unusual responses or anomalies in the measured transfer function.

*Standards and Guidelines*

1. *IEEE C57.149*: Standard for the Present and Future Methods for Specifying and Testing the Performance of Winding Insulation in Transformers
2. *IEC 60076-1*: Power transformers - Part 1: General
3. *ANSI/NETA ATS*: Standard for Acceptance Testing Specifications for Electrical Power Distribution Equipment and Systems

07/12/2024

https://youtu.be/dVd_07iB9dA?si=ISLZqsxQG7CcmQy0

The Capacitor and Dissipation Factor (CD) test, also known as the Dissipation Factor (DF) or Power Factor (PF) test, is a diagnostic test performed on transformers to evaluate the condition of the insulation system.

*Objective:*

The primary objective of the CD test is to assess the insulation's ability to withstand electrical stress and detect any potential issues, such as:

1. Moisture ingress
2. Insulation degradation
3. Contamination

*Test Methodology:*

1. *Measurement Setup*: The test is typically performed using a specialized instrument, such as a Schering bridge or a modern insulation tester.
2. *Voltage Application*: A known AC voltage (usually 100 Hz to 1000 Hz) is applied across the transformer's winding.
3. *Current Measurement*: The resulting current is measured, and the power factor (PF) or dissipation factor (DF) is calculated.
4. *Capacitance Measurement*: The capacitance between the winding and ground, as well as between windings, is measured.

*Parameters Measured:*

1. *Dissipation Factor (DF)*: The ratio of the active power (watts) to the reactive power (VARs).
2. *Power Factor (PF)*: The ratio of the active power (watts) to the apparent power (VA).
3. *Capacitance*: The ability of the insulation to store electric charge.

*Interpretation:*

1. *DF and PF Values*: A high DF or PF value indicates poor insulation quality, moisture ingress, or contamination.
2. *Capacitance Values*: A significant change in capacitance values can indicate insulation degradation or moisture ingress.

*Acceptance Criteria:*

1. *DF and PF Values*: Typically, DF values should be below 0.5% to 1.0%, and PF values should be above 0.95 to 0.99.
2. *Capacitance Values*: The capacitance values should be within the manufacturer's specified limits or compared to previous measurements.

Watch & Subscribe"Capacitance & Discipation Factor/Tan Delta Test of Transformer (C&DF)" on YouTube https://youtu.be/dVd_07iB9dATransformer Oil Dielectric St...

04/12/2024

Anti-Pumping:

Anti-pumping is a protection feature in circuit breakers that prevents the breaker from repeatedly opening and closing (or "pumping") when a fault is present.

Causes of Pumping:

1. _Faults in the power system_: Faults such as short circuits, ground faults, or overcurrent conditions can cause the circuit breaker to pump.
2. _Incorrect breaker settings_: Incorrect settings of the circuit breaker, such as over-sensitive or under-sensitive settings, can cause pumping.
3. _Worn or faulty breaker components_: Worn or faulty components, such as contacts or springs, can cause the breaker to pump.

Effects of Pumping:

1. _Equipment damage_: Repeated opening and closing of the circuit breaker can cause equipment damage, such as worn contacts or broken springs.
2. _Power system instability_: Pumping can cause power system instability, leading to voltage fluctuations, frequency deviations, and even power outages.
3. _Safety hazards_: Pumping can create safety hazards, such as electrical shocks or arc flashes.

Anti-Pumping Techniques:

1. _Anti-pumping relays_: Specialized relays that detect pumping conditions and prevent the circuit breaker from opening and closing repeatedly.
2. _Breaker control algorithms_: Advanced algorithms that control the circuit breaker's opening and closing sequence to prevent pumping.
3. _Circuit breaker design modifications_: Design modifications to the circuit breaker, such as improved contact designs or spring materials, can help prevent pumping.

01/12/2024

Closing Coil Supervision Relay:

_Overview_

A Closing Coil Supervision Relay is a type of protective relay used to monitor the closing coil of a circuit breaker. The relay ensures that the closing coil is functioning correctly and that the circuit breaker can close reliably.

_Functionality_

1. _Monitoring closing coil voltage_: The relay monitors the voltage applied to the closing coil.
2. _Detecting closing coil faults_: The relay detects faults such as short circuits, open circuits, or incorrect voltage levels.
3. _Tripping the circuit breaker_: If a fault is detected, the relay sends a signal to trip the circuit breaker.
4. _Alarming and indication_: The relay provides alarming and indication of the fault condition.

_Types of Closing Coil Supervision Relays_

1. _Voltage-based relays_: Monitor the voltage applied to the closing coil.
2. _Current-based relays_: Monitor the current flowing through the closing coil.
3. _Hybrid relays_: Combine voltage and current monitoring.

_Benefits_

1. _Improved reliability_: Ensures that the circuit breaker can close reliably.
2. _Enhanced safety_: Prevents potential accidents caused by faulty closing coils.
3. _Reduced maintenance_: Detects faults early, reducing maintenance and repair costs.

28/11/2024

Low Impedance Busbar Protection (LIBP):

_Overview_

LIBP is a high-speed protection scheme used to protect busbars from faults. It's designed to detect faults quickly and accurately, even in complex busbar configurations.

_Principle of Operation_

LIBP uses a differential protection principle, where the currents entering and leaving the busbar are compared. The protection scheme detects faults by measuring the differential current, which is the difference between the incoming and outgoing currents.

_Key Components_

1. _Current Transformers (CTs)_: Measure the currents entering and leaving the busbar.
2. _Relay_: Compares the differential current and initiates tripping if a fault is detected.
3. _Tripping Circuit_: Initiates the tripping of the circuit breakers.

_Characteristics_

1. _High-Speed Operation_: LIBP operates in less than 1 cycle (typically 10-20 ms).
2. _High Sensitivity_: Detects faults with high accuracy, even in complex busbar configurations.
3. _Low Impedance_: Requires a low impedance busbar configuration to ensure accurate fault detection.

_Advantages_

1. _Fast Fault Detection_: Quickly detects faults, reducing the risk of damage to equipment.
2. _High Accuracy_: Accurately detects faults, reducing the risk of false tripping.
3. _Reliability_: Provides reliable protection for busbars, even in complex configurations.

_Applications_

1. _Power Plants_: Protects busbars in power plants, ensuring reliable operation.
2. _Substations_: Protects busbars in substations, ensuring reliable power transmission and distribution.
3. _Industrial Power Systems_: Protects busbars in industrial power systems, ensuring reliable operation.

_Standards and Guidelines_

1. _IEEE C37.234_: Standard for High-Speed Busbar Protection.
2. _IEC 61850_: Communication Networks and Systems for Power Utility Automation.