GE P642 User Manual

3.2 APPLICATION NOTES
3.2.1 LOL SETTING GUIDELINES
Set the life hours at the reference maximum Hotspot temperature. According to IEEE Std. C57.91-1995, the normal
insulation life at the r
eference temperature in hours or years must be user-defined. The following table extracted
from IEEE Std. C57.91-1995 gives values of normal insulation life for a well-dried, oxygen-free 65°C average
winding temperature rise insulation system at the reference temperature of 110°C.
Basis Normal Insulation life Hours Normal Insulation Life Years
50% retained tensile strength of insulation (former IEEE Std
C57.92-1981 criterion)
65000 7.42
25% retained tensile strength of insulation 135000 15.41
200 retained degree of polymerization in insulation 150000 17.12
Interpretation of distribution transformer functional life test
data (former IEEE S
td. C57.91-1981)
180000 20.55
Note:
T
ensile strength or degree of polymerization (D.P.) retention values were determined by sealed tube aging on well-dried
insulation samples in oxygen-free oil.
Note:
R
efer to I.2 in annex I of the IEEE Std. C57.91-1995 for discussion of the effect of higher values of water and oxygen and also
for the discussion on the basis given above.
You should set the designed Hotspot temperature setting (Designed HS t
emp) to 110°C if the transformer is rated
65°C average winding rise. If the transformer is rated 55°C average winding rise, set it to 95°C.
As recommended by IEEE C57.91-1995, set the Constant B Set setting to 5000.
If the calculated aging acceleration factor is greater than the setting FAA> Set and the time delay tFAA> Set has
elapsed, the FAA alarm DDB signal is activated.
If the calculated loss of life is greater than the setting LOL>1 Set and the time delay tLOL> Set has elapsed, the
LOL alarm DDB signal is activated.
3.2.2 EXAMPLE
Consider a new 65°C average winding rise rated transformer whose life hours figure at designed maximum
Hotspot temperatur
e is 180,000 hrs. As a result, you set the Life Hours at HS setting to 180,000, and the
Designed HS temp setting to 110.0°C. Set Constant B Set to 15,000 as recommended by IEEE. The aging
acceleration factor takes into consideration the constant B and the hottest spot temperature calculated by the
thermal function. For a distribution transformer, IEEE suggests 200°C as the limit for the maximum hot spot
temperature. The aging acceleration factor alarm will be asserted when 70% of the 200°C has been reached. The
aging acceleration factor is calculated as follows:
FAA e e
B B
hottest spot tempt
B B
= =
−
− − +






−
× +
383 273
383 0 7 200 273.






=17 2.
Therefore:
F
AA>set should be set to 17.2. tFAA> Set may be set to 10.00 min. LOL>1 Set may be set to 115,000 hrs, if
it is considered that the transformer has 65,000 hrs left (Life Hours at HS – hours left = 180,000 – 65,000 = 115,000
hrs). tLOL> Set may be set to 10.00 min. Finally, the Reset Life Hours setting determines the value of the LOL
Chapter 7 - Transformer Condition Monitoring P64x
152 P64x-TM-EN-1.3

GE P642 Specifications

General

Brand	GE
Model	P642
Category	Relays
Language	English

Summary

MiCOM P40 Agile Technical Manual

Chapter 1 Introduction

Product Scope

Details the capabilities and models within the MiCOM P64x range of devices.

Chapter 2 Safety Information

Health and Safety

Outlines personnel qualifications and general safety practices for operating the equipment.

Installation, Commissioning and Servicing

Covers hazards related to lifting, electrical safety, and general installation procedures.

Chapter 4 Software Design

Protection and Control Functions

Explains the processing of protection elements and measurement functions by the software.

Chapter 5 Configuration

Using the HMI Panel

Details how to navigate menus, change settings, and use keypad functions via the HMI.

Configuring the Data Protocols

Explains how to configure communication settings for various protocols like Courier, DNP3, IEC 60870-5-103, Modbus, and IEC 61850.

Chapter 6 Transformer Differential Protection

Transformer Differential Protection Principles

Explains the current differential principle, through-fault stability, and bias current compensation.

Implementation

Details defining the power transformer, selecting current inputs, phase correction, and ratio correction.

Harmonic Blocking

Chapter 7 Transformer Condition Monitoring

Thermal Overload Protection

Details thermal overload protection, including the thermal model and bias current calculations.

Loss of Life Statistics

Explains the implementation and calculation of loss of life statistics based on thermal models.

Through Fault Monitoring

Chapter 8 Restricted Earth Fault Protection

REF Protection Principles

Explains winding-to-core faults and the principles of REF protection for delta and star windings.

Restricted Earth Fault Protection Implementation

Details enabling REF protection, selecting current inputs, and low/high impedance REF principles.

Application Notes

Chapter 9 Current Protection Functions

Overcurrent Protection Principles

Explains the job of IEDs in protecting power systems from faults and IDMT characteristics.

Phase Overcurrent Protection

Details phase overcurrent protection implementation, including stages and directional elements.

Voltage Dependent Overcurrent Element

Negative Sequence Overcurrent Protection

Explains the use of negative sequence overcurrent elements for unbalanced fault conditions.

Earth Fault Protection

Chapter 10 CB Fail Protection

Circuit Breaker Fail Protection

Explains the role of CBF protection in monitoring circuit breakers and ensuring fault isolation.

Circuit Breaker Fail Implementation

Circuit Breaker Fail Logic

Application Notes

Provides setting guidelines for CB Fail timers and undercurrent elements.

Chapter 11 Voltage Protection Functions

Undervoltage Protection

Details undervoltage conditions and their implementation and logic.

Overvoltage Protection

Explains overvoltage conditions, implementation, logic, and setting guidelines.

Residual Overvoltage Protection

Negative Sequence Overvoltage Protection

Chapter 12 Frequency Protection Functions

Overfluxing Protection

Explains overfluxing conditions, implementation, logic, and setting guidelines.

Frequency Protection

Details underfrequency and overfrequency protection implementation and logic.

Chapter 14 Supervision

Voltage Transformer Supervision

Details the VTS function for detecting AC voltage input failures and blocking dependent protection.

Current Transformer Supervision

Explains CTS function for detecting AC current input failures and its impact on protection.

Trip Circuit Supervision

Describes TCS schemes for supervising trip coil and trip path status.

Chapter 16 Communications

Communication Interfaces

Serial Communication

Redundant Ethernet Communication

Data Protocols

Lists supported data protocols including Courier, MODBUS, IEC 60870-5-103, DNP 3.0, and IEC 61850.

Chapter 17 Cyber-Security

The Need for Cyber-Security

Cyber-Security Implementation

Details current cyber-security measures at IED and external levels.

Chapter 19 Commissioning Instructions

General Guidelines

Commissioning Test Menu

Product Checks

Details product checks to ensure no physical damage, correct functionality, and tolerance compliance.

Setting Checks

Checking the Differential Element

Protection Timing Checks

Onload Checks

Final Checks

Chapter 20 Maintenance and Troubleshooting

Maintenance

Covers periodic checks, alarm status, opto-isolators, output relays, and measurement accuracy.

Troubleshooting

Guides on identifying error conditions, power-up errors, and mal-operation during testing.

Chapter 21 Technical Specifications

Interfaces

Performance of Transformer Differential Protection and Monitoring Functions

Provides accuracy specifications for transformer differential protection and monitoring functions.

Performance of Current Protection Functions

Details accuracy specifications for overcurrent, directional, and negative sequence protection.

Performance of Voltage Protection Functions

Specifies accuracy for undervoltage, overvoltage, residual overvoltage, and negative sequence voltage protection.

Performance of Frequency Protection Functions

Performance of Monitoring and Control Functions

Power Supply

Input / Output Connections

Electromagnetic Compatibility