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A method and system for surge detection within a gas turbine engine, comprises: measuring the compressor discharge pressure (CDP) of the gas turbine over a period of time; determining a time derivative (CDP D ) of the measured (CDP) correcting the CDP D for altitude, (CDP DCOR ); estimating a sho

A method and system for surge detection within a gas turbine engine, comprises: measuring the compressor discharge pressure (CDP) of the gas turbine over a period of time; determining a time derivative (CDP D ) of the measured (CDP) correcting the CDP D for altitude, (CDP DCOR ); estimating a short-term average of CDP DCOR 2 ; estimating a short-term average of CDP DCOR ; and determining a short-term variance of corrected CDP rate of change (CDP roc ) based upon the short-term average of CDP DCOR and the short-term average of CDP DCOR 2 . The method and system then compares the short-term variance of corrected CDP rate of change with a pre-determined threshold (CDP proc ) and signals an output when CDP roc >CDP proc . The method and system provides a signal of a surge within the gas turbine engine when CDP roc remains>CDP proc for pre-determined period of time.

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1. A method of surge detection within a turbomachine compressor, comprising:measuring the compressor discharge pressure (CDP) of the turbomachine compressor over a period of time;determining a time derivative (CDP D ) of the measured (CDP);correcting the CDP D for altitude, (CDP DCOR )inputting C

1. A method of surge detection within a turbomachine compressor, comprising:measuring the compressor discharge pressure (CDP) of the turbomachine compressor over a period of time;determining a time derivative (CDP D ) of the measured (CDP);correcting the CDP D for altitude, (CDP DCOR )inputting CDP DCOR 2 into a first filter algorithm (FFA);inputting CDP DCOR into a second filter algorithm (SFA);estimating a short-term average of CDP DCOR 2 by using the FFA;estimating a short-term average of CDP DCOR by using the SFA;determining a short-term variance of corrected CDP D (CDP roc ) based upon the short-term average of CDP DCOR and the short-term average of CDP DCOR 2 ;comparing the short-term variance of CDP DCOR rate of change with a pre-determined threshold (CDP proc );signaling an output when CDP roc >CDP proc ; andsignaling an occurrence of a surge within the turbomachine compressor when CDP roc remains>CDP proc for pre-determined period of time. 2. The method of claim 1, further comprising:executing the first filter algorithm with a first digital filter; andexecuting the second filter algorithm with a second digital filler. 3. The method of claim 2, wherein the first filter algorithm is a rolling average of the most recent CDP DCOR 2 values and the second filter algorithm is a rolling average of the most recent CDP DCOR values. 4. The method of claim 3, wherein the first filter algorithm is calculated of the z most recent CDP DCOR 2 values and the second filter algorithm is calculated of the z most recent CDP DCOR values, where the short-term average of CDP DCOR 2 is equal to: E[CDP DCOR 2 ]( n )=[ CDP DCOR 2 ( n )+ CDP DCOR 2 ( n −1)+ CDP DCOR 2 ( n −2) . . . + CDP DCOR 2 ( n −( z −1))]/ z, where CDP DCOR 2 (n) is the n th sample of CDP DCOR 2 , and the short term average of CDP DCOR is equal to: E[CDP DCOR ]( n )=[ CDP DCOR ( n )+ CDP DCOR ( n −1)+ CDP DCOR ( n −2) . . . + CDP DCOR ( n −( z −1))]/ z , where CDP DCOR ( n ) is the n th sample of CDP DCOR . 5. The method of claim 2, where the first filter algorithm is a bilinear implementation of a first order lag and the second filter algorithm is a bilinear implementation of another first order lag. 6. The method of claim 5, wherein the short-term average of CDP DCOR 2 is equal to E[CDP DCOR 2 ]( n )˜ c 1 *E[CDP DCOR 2 ]( n −1)+((1 −c 1 )/2)* CDP DCOR 2 ( n )+((1 −c 1 )/2)* CDP DCOR 2 ( n −1)where CDP DCOR 2 (n) is the n th sample of CDP DCOR 2 and c 1 is a filter coefficient, and the short term average of CDP DCOR is equal to: E[CDP DCOR ]( n )˜ c 1 *E[CDP DCOR ]( n −1)+((1 −c 1 )/2)* CDP DCOR ( n )+((1 −c 1 )/2)* CDP DCOR ( n −1)where CDP DCOR (n) is the n th sample of CDP DCOR and c 1 is a filter coefficient. 7. The method of claim 1, further comprising:executing the first filter algorithm with a first analog filter; andexecuting the second filter algorithm with a second analog filter. 8. The method of claim 7, wherein the first analog filter is represented by the following equation to estimate a short term average of CDP DCOR 2 : E[CDP DCOR 2 ]( s )˜ CDP DCOR 2 ( s )/( Ts +1)where CDP DCOR 2 (s) is the frequency-domain representation of the CDP DCOR 2 and T is the time constant of the filter, and where the second analog filter is represented by the following equation to estimate the short term average of CDP DCOR : E[CDP DCOR ]( s )˜ CDP DCOR ( s )/( Ts +1).where CDP DCOR (s) is the frequency-domain representation of the CDP DCOR and T is the time constant of the filter. 9. The method of claim 4, wherein the step determining a short-term variance of corrected CDP rate of change (CDP roc ) based upon the short-te rm average of CDP DCOR (E 2 [CDP DCOR ]) and the short-term average of CDP DCOR 2 (E[CDP DCOR 2 ]), is executed by the following equation: Var[CDP DCOR ]=E[CDP DCOR 2 ]−E 2 [CDP DCOR ]. 10. The method of claim 6, wherein the step determining a short-term variance of corrected CDP rate of change (CDP roc ) based upon the short-term average of CDP DCOR (E 2 [CDP DCOR ]) and the short-term average of CDP DCOR 2 (E[CDP DCOR 2 ]), is executed by the following equation: Var[CDP DCOR ]=E[CDP DCOR 2 ]−E 2 [CDP DCOR ]. 11. The method of claim 8, wherein the step determining a short-term variance of corrected CDP rate of change (CDP roc ) based upon the short-term average of CDP DCOR (E 2 [CDP DCOR ]) and the short-term average of CDP DCOR 2 (E[CDP DCOR 2 ]) is executed by the following equation: Var[CDP DCOR ]=E[CDP DCOR 2 ]−E 2 [CDP DCOR ]. 12. A method of surge detection within a turbomachine compressor, comprising:measuring a compressor discharge pressure (CDP) of the turbomachine compressor over a period of time;determining a time derivative (CDP D ) of the measured (CDP);correcting the CDP D for altitude, (CDP DCOR );estimating a short-term average of CDP DCOR 2 by using a first filter algorithm (FFA);estimating a short-term average of CDP DCOR by using a second filter algorithm (SFA);determining a short-term variance of corrected CDP rate of change (CDP roc ) based upon the short-term average of CDP DCOR and the short-term average of CDP DCOR 2 ;comparing the short-term variance of corrected CDP rate of change with a pre-determined threshold (CDP proc );signaling an output when CDP roc >CDP proc ; andsignaling an occurrence of a surge within the turbomachine compressor when CDP roc remains>CDP proc for pre-determined period of time. 13. The method of claim 12, wherein a first digital filter performs the step of estimating a short-term average of CDP DCOR 2 , wherein a second digital filter performs the step of estimating a short-term average of CDP DCOR . 14. The method of claim 12, wherein a first analog filter performs the step of estimating a short-term average of CDP DCOR 2 , wherein a second analog filter performs the step of estimating a short term average of CDP DCOR . 15. The method of claim 13, wherein the first filter algorithm is a bilinear implementation of a first order lag and the second filter algorithm is a bilinear implementation of a first order lag. 16. The method of claim 15, wherein the short-term average of CDP DCOR 2 is equal to: E[CDP DCOR 2 ]( n )˜ c 1 *E[CDP DCOR 2 ]( n −1)+((1 −c 1 )/2)* CDP DCOR 2 ( n )+((1 −c 1 )/2)* CDP DCOR 2 ( n −1)where CDP DCOR 2 (n) is the n th sample of CDP DCOR 2 and wherein c 1 is a filter coefficient, and wherein the short term average of CDP DCOR is equal to: E[CDP DCOR ]( n )˜ c 1 *E[CDP DCOR ]( n −1)+((1 −c 1 )/2)* CDP DCOR ( n )+((1 −c 1 )/2)* CDP DCOR ( n −1)where CDP DCOR (n) is the n th sample of CDP DCOR and where c 1 is a filter coefficient. 17. The method of claim 13, where the first filter algorithm is a rolling average of the most recent CDP DCOR 2 values and the second filter algorithm is a rolling average of the most recent CDP DCOR values. 18. The method of claim 17, wherein the rolling average is calculated of the z most recent CDP DCOR 2 values, where the short-term average of CDP DCOR 2 is equal to: E[CDP DCOR 2 ]( n )=[ CDP DCOR 2 ( n )+ CDP DCOR 2 ( n −1)+ CDP DCOR 2 ( n −2) . . . + CDP DCOR 2 ( n −( z −1))]/ z where CDP DCOR 2 (n) is the n th sample of CDP DCOR 2 , and wherein the second filter algorithm is the rolling average is calculated of the z most recent CDP DCOR , and the short-term average of C DP DCOR is equal to: E[CDP DCOR ]( n )=[ CDP DCOR ( n )+ CDP DCOR ( n −1)+ CDP DCOR ( n −2) . . . + CDP DCOR ( n −( z −1))]/ z where CDP DCOR (n) is the n th sample of CDP DCOR . 19. The method of claim 14, wherein the first analog filter is represented by the following equation to estimate the short term average of CDP DCOR 2 : E[CDP DCOR 2 ]( s )˜ CDP DCOR 2 ( s )/( Ts +1)and wherein the second analog filter is represented by the following equation to estimate the short term average of CDP DCOR : E[CDP DCOR ]( s )˜ CDP DCOR ( s )/( Ts +1). 20. The method of claim 16, where the step determining a short-term variance of corrected CDP rate of change (CDP roc ) based upon the short-term average of CDP DCOR and the short-term average of CDP DCOR 2 , is executed by the following equation, Var[CDP DCOR ]=E[CDP DCOR 2 ]−E 2 [CDP DCOR ]. 21. The method of claim 18, where the step determining a short-term variance of corrected CDP rate of change (CDP roc ) based upon the short-term average of CDP DCOR and the short-term average of CDP DCOR 2 , is executed by the following equation, Var[CDP DCOR ]=E[CDP DCOR 2 ]−E 2 [CDP DCOR ]. 22. The method of claim 19, where the step determining a short-term variance of corrected CDP rate of change (CDP roc ) based upon the short-term average of CDP DCOR and the short-term average of CDP DCOR 2 , is executed by the following equation, Var[CDP DCOR ]=E[CDP DCOR 2 ]−E 2 [CDP DCOR ]. 23. A method of surge detection within a turbomachinery compressor, comprising:measuring the compressor discharge pressure (CDP) of the turbomachinery compressor over a period of time;determining a time derivative (CDP D ) of the measured (CDP);correcting the CDP D for altitude, (CDP DCOR );estimating a short-term average of CDP DCOR 2 ;estimating a short-term average of CDP DCOR ;determining a short-term variance of corrected CDP rate of change (CDP roc ) based upon the short-term average of CDP DCOR and the short-term average of CDP DCOR 2 ;comparing the short-term variance of CDP D rate of change with a pre-determined threshold (CDP proc );signaling an output when CDP roc >CDP proc ; andsignaling an occurrence of a surge within the turbomachinery compressor when CDP roc remains>CDP proc for pre-determined period of time. 24. The method of claim 23, where the step of estimating a short-term average of CDP DCOR 2 includes the step of executing a first filter algorithm with a first digital filter. 25. The method of claim 24, where step of estimating a short-term average of CDP DCOR includes the step of executing a second filter algorithm with a second digital filter. 26. The method of claim 23, where the step of estimating a short-term average of CDP DCOR 2 includes the step of executing a first filter algorithm with a first analog filter. 27. The method of claim 26, where step of estimating a short-term average of CDP D includes the step of executing a second filter algorithm with a second analog filter. 28. A method of surge detection within a turbomachinery compressor, comprising:digitally sampling the compressor discharge pressure (CDP) of the turbomachinery compressor over a period of time (T sample ) by using a compressor discharge pressure probe;determining a time derivative (CDP D ) of the measured (CDP), whereCDP D (n)=(CDP(n)−CDP (n− 1))/T sample , CDP(n) is the nth sample of CDP;correcting the CDP D for altitude, (CDP DCOR );inputting CDP DCOR 2 into a first filter algorithm (FFA);inputting CDP DCOR into a second filter algorithm (SFA);estimating a short-term average of CDP DCOR 2 (E[CDP DCOR 2 ](n)) by using the FFA which uses a rolling average of the z most recent CDP DCOR 2 where E[CDP DCOR 2 ]( n )=[ CDP DCOR 2 ( n )+ CDP DCOR 2 ( n −1)+ CD P DCOR 2 ( n −2) . . . + CDP DCOR 2 ( n −( z −1))]/ z; estimating a short-term average of CDP DCOR (E[CDP DCOR ](n)) by using the SFA which uses a rolling average of the z most recent CDP DCOR where E[CDP DCOR ]( n )=[ CDP DCOR ( n )+ CDP DCOR ( n −1)+ CDP DCOR ( n −2) . . . + CDP D ( n −( z −1))]/ z; determining a short-term variance of corrected CDP rate of change (Var[CDP DCOR ]) based upon E[CDP DCOR ] and E[CDP DCOR 2 ] where Var[CDP DCOR ]=E[CDP DCOR 2 ]−E 2 [CDP DCOR ];comparing the short-term variance of CDP rate of change with a pre-determined threshold (CDP proc );signaling an output when Var[CDP DCOR ]>CDP proc ; andsignaling an occurrence of a surge within the turbomachinery compressor when Var[CDP DCOR ]remains>CDP proc for pre-determined period of time. 29. A system for surge detection within a turbomachinery compressor, comprising:a compressor discharge probe that measures the compressor discharge pressure (CDP) of the turbomachinery compressor over a period of time;a signal processor that receives the CDP measurements from the compressor discharge probe, determines a time derivative (CDP D ) of the measured (CDP) and corrects the CDP D for altitude, (CDP DCOR );a first filter which receives CDP DCOR 2 and performs a first filter algorithm (FFA) that estimates a short-term average of CDP DCOR 2 ; anda second filter which receives CDP DCOR and performs a second filter algorithm (SFA) that estimates a short-term average of CDP DCOR , wherein the signal processor determines a short-term variance of corrected CDP rate of change (CDP roc ) based upon the short-term average of CDP DCOR and the short-term average of CDP DCOR 2 , compares the short-term variance of corrected CDP rate of change with a pre-determined threshold (CDP proc ), signals an output when CDP roc >CDP proc , and signals an occurrence of a surge within the turbomachinery compressor when CDP roc remains>CDP proc for pre-determined period of time. 30. The system for surge detection within a gas turbine engine according to claim 29, wherein the signal processor determines the time derivative over a pre-determined time interval. 31. The system for surge detection within a gas turbine engine according to claim 29, wherein the first filter is a first digital filter and the second filter is a second digital filter. 32. The system for surge detection within a gas turbine engine according to claim 29, wherein the first filter is a first analog filter and the second filter is a second analog filter.